Recent Submissions

  • Effectiveness of Coronavirus Disease 2019 Vaccines Against Hospitalization and Death in Canada: A Multiprovincial, Test-Negative Design Study

    Nasreen, Sharifa; Febriani, Yossi; Velásquez García, Héctor Alexander; Zhang, Geng; Tadrous, Mina; Buchan, Sarah A; Righolt, Christiaan H; Mahmud, Salaheddin M; Janjua, Naveed Zafar; Krajden, Mel; et al. (Oxford University Press (OUP), 2022-08-17)
    Background: A major goal of coronavirus disease 2019 (COVID-19) vaccination is to prevent severe outcomes (hospitalizations and deaths). We estimated the effectiveness of messenger RNA (mRNA) and ChAdOx1 COVID-19 vaccines against severe outcomes in 4 Canadian provinces between December 2020 and September 2021. Methods: We conducted this multiprovincial, retrospective, test-negative study among community-dwelling adults aged ≥18 years in Ontario, Quebec, British Columbia, and Manitoba using linked provincial databases and a common study protocol. Multivariable logistic regression was used to estimate province-specific vaccine effectiveness against COVID-19 hospitalization and/or death. Estimates were pooled using random-effects models. Results: We included 2 508 296 tested participants, with 31 776 COVID-19 hospitalizations and 5842 deaths. Vaccine effectiveness was 83% after a first dose and 98% after a second dose against both hospitalization and death (separately). Against severe outcomes, effectiveness was 87% (95% confidence interval [CI], 71%-94%) ≥84 days after a first dose of mRNA vaccine, increasing to 98% (95% CI, 96%-99%) ≥112 days after a second dose. Vaccine effectiveness against severe outcomes for ChAdOx1 was 88% (95% CI, 75%-94%) ≥56 days after a first dose, increasing to 97% (95% CI, 91%-99%) ≥56 days after a second dose. Lower 1-dose effectiveness was observed for adults aged ≥80 years and those with comorbidities, but effectiveness became comparable after a second dose. Two doses of vaccines provided very high protection for both homologous and heterologous schedules and against Alpha, Gamma, and Delta variants. Conclusions: Two doses of mRNA or ChAdOx1 vaccine provide excellent protection against severe outcomes.
  • Newborn and Early Infant Outcomes Following Maternal COVID-19 Vaccination During Pregnancy

    Jorgensen, Sarah C. J.; Drover, Samantha S. M.; Fell, Deshayne B.; Austin, Peter C.; D’Souza, Rohan; Guttmann, Astrid; Buchan, Sarah A.; Wilson, Sarah E.; Nasreen, Sharifa; Schwartz, Kevin L.; et al. (American Medical Association (AMA), 2023-12-01)
    Importance: The study team previously showed that maternal mRNA COVID-19 vaccination during pregnancy confers protection against SARS-CoV-2 infection and COVID-19-related hospital admission in newborns and young infants. In this study, the study team evaluated newborn and early infant safety outcomes following maternal messenger RNA (mRNA) COVID-19 vaccination during pregnancy, for which there is limited comparative epidemiological evidence. Objective: To determine if maternal mRNA COVID-19 vaccination during pregnancy is associated with adverse newborn and early infant outcomes. Design, setting, and participants: This population-based retrospective cohort study took place in Ontario, Canada, using multiple linked health administrative databases. Singleton live births with an expected delivery date between May 1, 2021, and September 2, 2022, were included. Data were analyzed from January 2023 through March 2023. Exposure: Maternal mRNA COVID-19 vaccination (1 or more doses) during pregnancy. Main outcomes and measures: Severe neonatal morbidity (SNM), neonatal death, neonatal intensive care unit (NICU) admission, neonatal readmission, and hospital admission up to 6 months of age. The study team calculated inverse probability of treatment weighted risk ratios (RRs) and fit weighted Cox proportional hazards regression models comparing outcomes in infants of mothers who received COVID-19 vaccination during pregnancy with those who received no COVID-19 vaccine doses before delivery. Results: In total, 142 006 infants (72 595 male [51%]; mean [SD] gestational age at birth, 38.7 [1.7] weeks) were included; 85 670 were exposed to 1 or more COVID-19 vaccine doses in utero (60%). Infants of vaccinated mothers had lower risks of SNM (vaccine exposed 7.3% vs vaccine unexposed 8.3%; adjusted RR [aRR], 0.86; 95% CI, 0.83-0.90), neonatal death (0.09% vs 0.16%; aRR, 0.47; 95% CI, 0.33-0.65), and NICU admission (11.4% vs 13.1%; aRR, 0.86; 95% CI, 0.83-0.89). There was no association between maternal vaccination during pregnancy and neonatal readmission (5.5% vs 5.1%; adjusted hazard ratio, 1.03; 95% CI, 0.98-1.09) or 6-month hospital admission (8.4% vs 8.1%; adjusted hazard ratio, 1.01; 95% CI, 0.96-1.05). Conclusions and relevance: In this population-based cohort study in Ontario, Canada, maternal mRNA COVID-19 vaccination during pregnancy was associated with lower risks of SNM, neonatal death, and NICU admission. In addition, neonatal and 6-month readmissions were not increased in infants of mothers vaccinated during pregnancy.
  • Novel multiplex assay platforms to detect influenza A hemagglutinin subtype‐specific antibody responses for high‐throughput and in‐field applications

    Li, Zhu‐Nan; Trost, Jessica F.; Weber, Kimberly M.; LeMasters, Elizabeth H.; Nasreen, Sharifa; Esfandiari, Javan; Gunasekera, Angelo H.; McCausland, Megan; Sturm‐Ramirez, Katharine; Wrammert, Jens; et al. (Wiley, 2017-04-05)
    Background: Detections of influenza A subtype-specific antibody responses are often complicated by the presence of cross-reactive antibodies. We developed two novel multiplex platforms for antibody detection. The multiplexed magnetic fluorescence microsphere immunoassay (MAGPIX) is a high-throughput laboratory-based assay. Chembio Dual Path Platform (DPP) is a portable and rapid test that could be used in the field. Methods: Twelve recombinant globular head domain hemagglutinin (GH HA1) antigens from A(H1N1)pdm09 (pH1N1), A(H2N2), A(H3N2), A(H5N1), A(H7N9), A(H9N2), A(H13N9), B/Victoria lineage, B/Yamagata lineage viruses, and protein A control were used. Human sera from U.S. residents either vaccinated (with H5N1 or pH1N1) or infected with pH1N1 influenza viruses and sera from live bird market workers in Bangladesh (BDPW) were evaluated. GH HA1 antigens and serum adsorption using full ectodomain recombinant hemagglutinins from A(pH1N1) and A(H3N2) were introduced into the platforms to reduce cross-reactivity. Results: Serum adsorption reduced cross-reactivity to novel subtype HAs. Compared to traditional hemagglutination inhibition or microneutralization assays, when serum adsorption and the highest fold rise in signals were used to determine positivity, the correct subtype-specific responses were identified in 86%-100% of U.S. residents exposed to influenza antigens through vaccination or infection (N=49). For detection of H5N1-specific antibodies in sera collected from BDPW, H5 sensitivity was 100% (six of six) for MAGPIX, 83% (five of six) for DPP, H5 specificity was 100% (15/15), and cross-reactivity against other subtype was 0% (zero of six) for both platforms. Conclusion: MAGPIX and DPP platforms can be utilized for high-throughput and in-field detection of novel influenza virus infections.
  • Understanding community perceptions, social norms and current practice related to respiratory infection in Bangladesh during 2009: a qualitative formative study

    Nizame, Fosiul A; Nasreen, Sharifa; Unicomb, Leanne; Southern, Dorothy; Gurley, Emily S; Arman, Shaila; Kadir, Mohammad A; Azziz-Baumgartner, Eduardo; Luby, Stephen P; Winch, Peter J (Springer Science and Business Media LLC, 2011-12-04)
    Background: Respiratory infections are the leading cause of childhood deaths in Bangladesh. Promoting respiratory hygiene may reduce infection transmission. This formative research explored community perceptions about respiratory infections. Methods: We conducted 34 in-depth interviews and 16 focus group discussions with community members and school children to explore respiratory hygiene related perceptions, practices, and social norms in an urban and a rural setting. We conducted unstructured observations on respiratory hygiene practices in public markets. Results: Informants were not familiar with the term "respiratory infection"; most named diseases that had no relation to respiratory dysfunction. Informants reported that their community identified a number of 'good behaviors' related to respiratory hygiene, but they also noted, and we observed, that very few people practiced these. All informants cited hot/cold weather changes or using cold water as causes for catching cold. They associated transmission of respiratory infections with close contact with a sick person's breath, cough droplets, or spit; sharing a sick person's utensils and food. Informants suggested that avoiding such contact was the most effective method to prevent respiratory infection. Although informants perceived that handwashing after coughing or sneezing might prevent illness, they felt this was not typically feasible or practical. Conclusion: Community perceptions of respiratory infections include both concerns with imbalances between hot and cold, and with person-to-person transmission. Many people were aware of measures that could prevent respiratory infection, but did not practice them. Interventions that leverage community understanding of person-to-person transmission and that encourage the practice of their identified 'good behaviors' related to respiratory hygiene may reduce respiratory disease transmission.
  • Early Detection of Pandemic (H1N1) 2009, Bangladesh

    Azziz-Baumgartner, Eduardo; Rahman, Mustafizur; Al Mamun, Abdullah; Haider, Mohammad Sabbir; Zaman, Rashid Uz; Karmakar, Polash Chandra; Nasreen, Sharifa; Muneer, Syeda Mah-E; Homaira, Nusrat; Goswami, Doli Rani; et al. (Centers for Disease Control and Prevention (CDC), 2012-01)
    To explore Bangladesh's ability to detect novel influenza, we examined a series of laboratory-confirmed pandemic (H1N1) 2009 cases. During June-July 2009, event-based surveillance identified 30 case-patients (57% travelers); starting July 29, sentinel sites identified 252 case-patients (1% travelers). Surveillance facilitated response weeks before the spread of pandemic (H1N1) 2009 infection to the general population.
  • Impact of an Intensive Perinatal Handwashing Promotion Intervention on Maternal Handwashing Behavior in the Neonatal Period: Findings from a Randomized Controlled Trial in Rural Bangladesh

    Ram, Pavani Kalluri; Nasreen, Sharifa; Kamm, Kelly; Allen, Jelena; Kumar, Swapna; Rahman, Mohammad Anisur; Zaman, K.; El Arifeen, Shams; Luby, Stephen P. (Hindawi Limited, 2017)
    One-quarter of neonatal deaths are attributed to infections. Maternal handwashing with soap may prevent neonatal sepsis. We examined impact of intensive handwashing promotion on handwashing behavior of mothers of neonates. In Matlab, Bangladesh, we randomly allocated pregnant women at 28-32 weeks' gestation to intensive handwashing promotion or control. Behavior change communicators used a participatory approach to motivate maternal handwashing with soap and provided soap and handwashing stations. In the neonatal period, we observed soap and water at handwashing places and, at the end of the neonatal period, we estimated impact on maternal handwashing by structured observation. Among 253 women enrolled, intervention households were between 5.7 and 15.2 times as likely as control households to have soap and water present at the handwashing station in the baby's sleeping area. Intervention mothers washed hands with soap 4.1 times as frequently as controls (95% CI 2.55-6.59); handwashing with soap at recommended times was infrequent in both intervention (9%) and control (2%) groups. Intensively promoting handwashing with soap resulted in increased availability of soap and water at handwashing places, but only a modest increase in maternal handwashing with soap. Novel approaches to motivating handwashing behavior to protect newborns should be developed and evaluated.
  • Maternal mRNA covid-19 vaccination during pregnancy and delta or omicron infection or hospital admission in infants: test negative design study

    Jorgensen, Sarah C J; Hernandez, Alejandro; Fell, Deshayne B; Austin, Peter C; D’Souza, Rohan; Guttmann, Astrid; Brown, Kevin A; Buchan, Sarah A; Gubbay, Jonathan B; Nasreen, Sharifa; et al. (BMJ, 2023-02-08)
    Objective: To estimate the effectiveness of maternal mRNA covid-19 vaccination during pregnancy against delta and omicron severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and hospital admission in infants. Design: Test negative design study. Setting: Community and hospital testing in Ontario, Canada. Participants: Infants younger than six months of age, born between 7 May 2021 and 31 March 2022, who were tested for SARS-CoV-2 between 7 May 2021 and 5 September 2022. Intervention: Maternal mRNA covid-19 vaccination during pregnancy. Main outcome measures: Laboratory confirmed delta or omicron infection or hospital admission of the infant. Multivariable logistic regression estimated vaccine effectiveness, with adjustments for clinical and sociodemographic characteristics associated with vaccination and infection. Results: 8809 infants met eligibility criteria, including 99 delta cases (4365 controls) and 1501 omicron cases (4847 controls). Infant vaccine effectiveness from two maternal doses was 95% (95% confidence interval 88% to 98%) against delta infection and 97% (73% to 100%) against infant hospital admission due to delta and 45% (37% to 53%) against omicron infection and 53% (39% to 64%) against hospital admission due to omicron. Vaccine effectiveness for three doses was 73% (61% to 80%) against omicron infection and 80% (64% to 89%) against hospital admission due to omicron. Vaccine effectiveness for two doses against infant omicron infection was highest with the second dose in the third trimester (53% (42% to 62%)) compared with the first (47% (31% to 59%)) or second (37% (24% to 47%)) trimesters. Vaccine effectiveness for two doses against infant omicron infection decreased from 57% (44% to 66%) between birth and eight weeks to 40% (21% to 54%) after 16 weeks of age. Conclusions: Maternal covid-19 vaccination with a second dose during pregnancy was highly effective against delta and moderately effective against omicron infection and hospital admission in infants during the first six months of life. A third vaccine dose bolstered protection against omicron. Effectiveness for two doses was highest with maternal vaccination in the third trimester, and effectiveness decreased in infants beyond eight weeks of age.
  • Effectiveness of mRNA COVID-19 vaccine booster doses against Omicron severe outcomes

    Grewal, Ramandip; Nguyen, Lena; Buchan, Sarah A.; Wilson, Sarah E.; Nasreen, Sharifa; Austin, Peter C.; Brown, Kevin A.; Fell, Deshayne B.; Gubbay, Jonathan B.; Schwartz, Kevin L.; et al. (Springer Science and Business Media LLC, 2023-03-07)
    We estimated the effectiveness of booster doses of monovalent mRNA COVID-19 vaccines against Omicron-associated severe outcomes among adults in Ontario, Canada. We used a test-negative design to estimate vaccine effectiveness (VE) against hospitalization or death among SARS-CoV-2-tested adults aged ≥50 years from January 2 to October 1, 2022, stratified by age and time since vaccination. We also compared VE during BA.1/BA.2 and BA.4/BA.5 sublineage predominance. We included 11,160 cases and 62,880 tests for test-negative controls. Depending on the age group, compared to unvaccinated adults, VE was 91–98% 7–59 days after a third dose, waned to 76–87% after ≥240 days, was restored to 92–97% 7–59 days after a fourth dose, and waned to 86–89% after ≥120 days. VE was lower and declined faster during BA.4/BA.5 versus BA.1/BA.2 predominance, particularly after ≥120 days. Here we show that booster doses of monovalent mRNA COVID-19 vaccines restored strong protection against severe outcomes for at least 3 months after vaccination. Across the entire study period, protection declined slightly over time, but waned more during BA.4/BA.5 predominance.
  • Barriers to and motivators of handwashing behavior among mothers of neonates in rural Bangladesh

    Parveen, Shahana; Nasreen, Sharifa; Allen, Jelena V.; Kamm, Kelly B.; Khan, Shifat; Akter, Shirina; Lopa, Tajnin Marin; Zaman, K.; El Arifeen, Shams; Luby, Stephen P.; et al. (Springer Science and Business Media LLC, 2018-04-11)
    Background: To design a maternal handwashing intervention for the newborn period, this qualitative study explored drivers of handwashing among mothers and other caregivers of neonates and infants in two rural areas of Bangladesh. Methods: We conducted 40 semi-structured observation sessions to observe handwashing behaviors of primiparous and multiparous mothers of neonates, and to understand the contextual factors that facilitated or hampered those behaviors. We then conducted 64 interviews with mothers of neonates and mothers of infants and 6 group discussions with mothers of infants, other female caregivers and fathers to explore perceptions, beliefs, and practices related to handwashing in the neonatal period. Based on a conceptual model and the Theory of Reasoned Action/Theory of Planned Behavior, we developed a conceptual model a priori, we performed thematic analysis to explain determinants of maternal handwashing behaviors. Results: We conducted 200 h of observation among mothers of neonates. The age range of participating mothers varied between 17 and 25 years and their maximum education was up to 10th grade of schooling. Mothers, other female caregivers and fathers perceived a need to wash hands with or without soap before eating or before feeding a child by hand to prevent diarrhea. Mothers expressed the importance of washing their hands before holding a baby but were rarely observed doing so. All respondents prioritized using soap for visible dirt or feces; otherwise, water alone was considered sufficient. Lack of family support, social norms of infrequent handwashing, perceptions of frequent contact with water as a health threat and mothers' restricted movement during first 40 days of neonate's life, and childcare and household responsibilities adversely impacted handwashing behavior. Conclusions: Addressing emotive drivers of handwashing within existing social norms by engaging family members, ensuring handwashing facilities and clarifying neonatal health threats may improve maternal handwashing behavior in the neonatal period.
  • Seroprevalence of Antibodies against Highly Pathogenic Avian Influenza A (H5N1) Virus among Poultry Workers in Bangladesh, 2009

    Nasreen, Sharifa; Uddin Khan, Salah; Azziz-Baumgartner, Eduardo; Hancock, Kathy; Veguilla, Vic; Wang, David; Rahman, Mahmudur; Alamgir, A. S. M.; Sturm-Ramirez, Katharine; Gurley, Emily S.; et al. (Public Library of Science (PLoS), 2013-09-05)
    We conducted a cross-sectional study in 2009 to determine the seroprevalence and risk factors for highly pathogenic avian influenza A (H5N1) [HPAI H5N1] virus antibodies among poultry workers at farms and live bird markets with confirmed/suspected poultry outbreaks during 2009 in Bangladesh. We tested sera by microneutralization assay using A/Bangladesh/207095/2008 (H5N1; clade 2.2.2) virus with confirmation by horse red blood cell hemagglutination inhibition and H5-specific Western blot assays. We enrolled 212 workers from 87 farms and 210 workers from three live bird markets. One hundred and two farm workers (48%) culled poultry. One hundred and ninety-three farm workers (91%) and 178 market workers (85%) reported direct contact with poultry that died during a laboratory confirmed HPAI H5N1 poultry farm outbreak or market poultry die-offs from suspected HPAI H5N1. Despite exposure to sick poultry, no farm or market poultry workers were seropositive for HPAI H5N1 virus antibodies (95% confidence interval 0-1%).
  • Observed Practices and Perceived Advantages of Different Hand Cleansing Agents in Rural Bangladesh: Ash, Soil, and Soap

    Nizame, Fosiul A.; Unicomb, Leanne; Luby, Stephen P.; Arman, Shaila; Winch, Peter J.; Nasreen, Sharifa; Halder, Amal K. (American Society of Tropical Medicine and Hygiene, 2015-06-03)
    Bangladeshi communities have historically used ash and soil as handwashing agents. A structured observation study and qualitative interviews on the use of ash/soil and soap as handwashing agents were conducted in rural Bangladesh to help develop a handwashing promotion intervention. The observations were conducted among 1,000 randomly selected households from 36 districts. Fieldworkers observed people using ash/soil to wash their hand(s) on 13% of occasions after defecation and on 10% after cleaning a child's anus. This compares with 19% of people who used soap after defecation and 27% after cleaning a child who defecated. Using ash/soil or soap was rarely (< 1%) observed at other times recommended for handwashing. The qualitative study enrolled 24 households from three observation villages, where high usage of ash/soil for handwashing was detected. Most informants reported that ash/soil was used only for handwashing after fecal contact, and that ash/soil could clean hands as effectively as soap.
  • Prevalent high-risk respiratory hygiene practices in urban and rural Bangladesh

    Nasreen, S.; Azziz-Baumgartner, E.; Gurley, E. S.; Winch, P. J.; Unicomb, L.; Sharker, M. A. Y.; Southern, D.; Luby, S. P. (Wiley, 2010-03-30)
    Objectives: To identify existing respiratory hygiene risk practices, and guide the development of interventions for improving respiratory hygiene. Methods: We selected a convenience sample of 80 households and 20 schools in two densely populated communities in Bangladesh, one urban and one rural. We observed and recorded respiratory hygiene events with potential to spread viruses such as coughing, sneezing, spitting and nasal cleaning using a standardized assessment tool. Results: In 907 (81%) of 1122 observed events, households' participants coughed or sneezed into the air (i.e. uncovered), 119 (11%) into their hands and 83 (7%) into their clothing. Twenty-two per cent of women covered their coughs and sneezes compared to 13% of men (OR 2.6, 95% CI 1.6-4.3). Twenty-seven per cent of persons living in households with a reported monthly income of >72.6 US$ covered their coughs or sneezes compared to 13% of persons living in households with lower income (OR 3.2, 95% CI 1.6-6.2). In 956 (85%) of 1126 events, school participants coughed or sneezed into the air and 142 (13%) into their hands. Twenty-seven per cent of coughs/sneezes in rural schools were covered compared to 10% of coughs/sneezes in urban schools (OR 2.3, 95% CI 1.5-3.6). Hand washing was never observed after participants coughed or sneezed into their hands. Conclusion: There is an urgent need to develop culturally appropriate, cost-effective and scalable interventions to improve respiratory hygiene practices and to assess their effectiveness in reducing respiratory pathogen transmission.
  • Highly Pathogenic Avian Influenza A(H5N1) Virus Infection among Workers at Live Bird Markets, Bangladesh, 2009–2010

    Nasreen, Sharifa; Khan, Salah Uddin; Luby, Stephen P.; Gurley, Emily S.; Abedin, Jaynal; Zaman, Rashid Uz; Sohel, Badrul Munir; Rahman, Mustafizur; Hancock, Kathy; Levine, Min Z.; et al. (Centers for Disease Control and Prevention (CDC), 2015-04)
    The risk for influenza A(H5N1) virus infection is unclear among poultry workers in countries where the virus is endemic. To assess H5N1 seroprevalence and seroconversion among workers at live bird markets (LBMs) in Bangladesh, we followed a cohort of workers from 12 LBMs with existing avian influenza surveillance. Serum samples from workers were tested for H5N1 antibodies at the end of the study or when LBM samples first had H5N1 virus-positive test results. Of 404 workers, 9 (2%) were seropositive at baseline. Of 284 workers who completed the study and were seronegative at baseline, 6 (2%) seroconverted (7 cases/100 poultry worker-years). Workers who frequently fed poultry, cleaned feces from pens, cleaned food/water containers, and did not wash hands after touching sick poultry had a 7.6 times higher risk for infection compared with workers who infrequently performed these behaviors. Despite frequent exposure to H5N1 virus, LBM workers showed evidence of only sporadic infection.
  • Population-Based Incidence of Severe Acute Respiratory Virus Infections among Children Aged &lt;5 Years in Rural Bangladesh, June–October 2010

    Nasreen, Sharifa; Luby, Stephen P.; Brooks, W. Abdullah; Homaira, Nusrat; Mamun, Abdullah Al; Bhuiyan, Mejbah Uddin; Rahman, Mustafizur; Ahmed, Dilruba; Abedin, Jaynal; Rahman, Mahmudur; et al. (Public Library of Science (PLoS), 2014-02-25)
    Background: Better understanding the etiology-specific incidence of severe acute respiratory infections (SARIs) in resource-poor, rural settings will help further develop and prioritize prevention strategies. To address this gap in knowledge, we conducted a longitudinal study to estimate the incidence of SARIs among children in rural Bangladesh. Methods: During June through October 2010, we followed children aged <5 years in 67 villages to identify those with cough, difficulty breathing, age-specific tachypnea and/or danger signs in the community or admitted to the local hospital. A study physician collected clinical information and obtained nasopharyngeal swabs from all SARI cases and blood for bacterial culture from those hospitalized. We tested swabs for respiratory syncytial virus (RSV), influenza viruses, human metapneumoviruses, adenoviruses and human parainfluenza viruses 1-3 (HPIV) by real-time reverse transcription polymerase chain reaction. We calculated virus-specific SARI incidence by dividing the number of new illnesses by the person-time each child contributed to the study. Results: We followed 12,850 children for 279,029 person-weeks (pw) and identified 141 SARI cases; 76 (54%) at their homes and 65 (46%) at the hospital. RSV was associated with 7.9 SARI hospitalizations per 100,000 pw, HPIV3 2.2 hospitalizations/100,000 pw, and influenza 1.1 hospitalizations/100,000 pw. Among non-hospitalized SARI cases, RSV was associated with 10.8 illnesses/100,000 pw, HPIV3 1.8/100,000 pw, influenza 1.4/100,000 pw, and adenoviruses 0.4/100,000 pw. Conclusion: Respiratory viruses, particularly RSV, were commonly associated with SARI among children. It may be useful to explore the value of investing in prevention strategies, such as handwashing and respiratory hygiene, to reduce respiratory infections among young children in such settings.
  • Avian influenza surveillance in domestic waterfowl and environment of live bird markets in Bangladesh, 2007–2012

    Khan, Salah Uddin; Gurley, Emily S.; Gerloff, Nancy; Rahman, Md Z.; Simpson, Natosha; Rahman, Mustafizur; Haider, Najmul; Chowdhury, Sukanta; Balish, Amanda; Zaman, Rashid Uz; et al. (Springer Science and Business Media LLC, 2018-06-20)
    Avian influenza viruses, including highly pathogenic strains, pose severe economic, animal and public health concerns. We implemented live bird market surveillance in Bangladesh to identify the subtypes of avian influenza A viruses in domestic waterfowl and market environments. We collected waterfowl samples monthly from 4 rural sites from 2007 to 2012 and environmental samples from 4 rural and 16 urban sites from 2009 to 2012. Samples were tested through real-time RT-PCR, virus culture, and sequencing to detect and characterize avian influenza A viruses. Among 4,308 waterfowl tested, 191 (4.4%) were positive for avian influenza A virus, including 74 (1.9%) avian influenza A/H5 subtype. The majority (99%, n = 73) of the influenza A/H5-positive samples were from healthy appearing waterfowl. Multiple subtypes, including H1N1, H1N3, H3N2, H3N6, H3N8, H4N1, H4N2, H4N6, H5N1 (clades 2.2.2, 2.3.2.1a, 2.3.4.2), H5N2, H6N1, H7N9, H9N2, H11N2 and H11N3, H11N6 were detected in waterfowl and environmental samples. Environmental samples tested positive for influenza A viruses throughout the year. Avian influenza viruses, including H5N1 and H9N2 subtypes were also identified in backyard and small-scale raised poultry. Live bird markets could be high-risk sites for harboring the viruses and have the potential to infect naive birds and humans exposed to them.
  • Food adulteration and consumer awareness in Dhaka City, 1995-2011.

    Nasreen, Sharifa; Ahmed, Tahmeed (2014-09)
    We conducted this study to investigate the magnitude of food adulteration during 1995-2011 and consumer awareness in Dhaka city. We reviewed results of food sample testing by Public Health Food Laboratory of Dhaka City Corporation, Bangladesh Standards and Testing Institution, Consumers Association of Bangladesh publications, reports from lay press, including those on mobile magistrate court operations. We conducted a cross-sectional survey among 96 residents of Dhaka city, using a structured questionnaire in 2006. The overall proportion of food samples adulterated decreased during 2001-2005, and 40-54% of daily-consumed food was adulterated during 1995-2011. More than 35 food items were commonly adulterated. Consumers considered expiry date and quality or freshness as the best criteria while buying packaged and open food items respectively; only 11 (12%) respondents considered approval of regulatory authority for buying packaged food items. More than half of the food consumed in Dhaka city is adulterated, which warrants actions by the Government, the industry, and the consumers.
  • Prevalence of Latent Tuberculosis among Health Care Workers in High Burden Countries: A Systematic Review and Meta-Analysis

    Nasreen, Sharifa; Shokoohi, Mostafa; Malvankar-Mehta, Monali S. (Public Library of Science (PLoS), 2016-10-06)
    Background: Tuberculosis is one of the leading causes of death worldwide. Twenty-two high burden countries contributed to the majority of worldwide tuberculosis cases in 2015. Health care workers are at high risk of acquiring tuberculosis through occupational exposure. Objective: To estimate the prevalence of latent tuberculosis infection (LTBI) among health care workers in high burden countries. Methods: Databases including MEDLINE (Ovid), EMBASE (Ovid), CINAHL (Ovid) and ISI Web of Science (Thompson-Reuters), and grey literature were searched for English language records on relevant medical subject headings (MeSH) terms of LTBI and health care providers. Literature was systematically reviewed using EPPI-Reviewer4 software. Prevalence and incidence of LTBI and 95% confidence intervals (CI) were reported. Pooled prevalence of LTBI and 95% CI were calculated using random-effects meta-analysis models and heterogeneity was assessed using I2 statistics. Sub-group analysis was conducted to assess the cause of heterogeneity. Results: A total of 990 records were identified. Of those, 18 studies from only 7 high burden countries representing 10,078 subjects were included. Tuberculin skin test results were available for 9,545 participants. The pooled prevalence of LTBI was 47% (95% CI 34% to 60%, I2 = 99.6%). In subgroup analyses according to the country of the study, the pooled prevalence of LTBI was lowest in Brazil (37%) and highest in South Africa (64%). The pooled prevalence of LTBI among medical and nursing students was 26% (95% CI 6% to 46%, I2 = 99.3%) while the prevalence among all types of health care workers was 57% (95% CI 44% to 70%, I2 = 99.1%). Incidence of LTBI was available for health care workers in four countries. The cumulative incidence ranged from 2.8% in Brazilian medical students to 38% among all types of health care workers in South Africa. Conclusion: The findings of this study suggest that there is a high burden of LTBI among health care workers in high burden countries. Adequate infection control measures are warranted to prevent and control transmission in health care settings.
  • Epidemiology of Myocarditis and Pericarditis Following mRNA Vaccination by Vaccine Product, Schedule, and Interdose Interval Among Adolescents and Adults in Ontario, Canada

    Buchan, Sarah A.; Seo, Chi Yon; Johnson, Caitlin; Alley, Sarah; Kwong, Jeffrey C.; Nasreen, Sharifa; Calzavara, Andrew; Lu, Diane; Harris, Tara M.; Yu, Kelly; et al. (American Medical Association (AMA), 2022-06-24)
    Importance: Increased rates of myocarditis or pericarditis following receipt of COVID-19 mRNA vaccines have been observed. However, few available data are associated with differences in rates of myocarditis or pericarditis specific to vaccine products, which may have important implications for vaccination programs. Objective: To estimate rates of reported myocarditis or pericarditis following receipt of a COVID-19 mRNA vaccine by product, age, sex, dose number, and interdose interval. Design, setting, and participants: This population-based cohort study was conducted in Ontario, Canada (population: 14.7 million) from December 2020 to September 2021 and used data from Ontario's COVID-19 vaccine registry and passive vaccine-safety surveillance system. All individuals in Ontario, Canada, who received at least 1 dose of COVID-19 mRNA vaccine between December 14, 2020, and September 4, 2021, and had a reported episode of myocarditis or pericarditis following receipt of the COVID-19 vaccine during this period were included. We obtained information on all vaccine doses administered in the province to calculate reported rates of myocarditis or pericarditis. Exposures: Receipt of a COVID-19 mRNA vaccine (mRNA-1273 [Moderna Spikevax] or BNT162b2 [Pfizer-BioNTech Comirnaty]). Main outcomes and measures: All reports of myocarditis or pericarditis meeting levels 1 to 3 of the Brighton Collaboration case definitions were included. Rates and 95% CIs of reported cases of myocarditis or pericarditis per 1 000 000 mRNA vaccine doses administered were calculated by age, sex, dose number, vaccine product, and interdose interval. Results: Among 19 740 741 doses of mRNA vaccines administered, there were 297 reports of myocarditis or pericarditis meeting the inclusion criteria; 228 (76.8%) occurred in male individuals, and the median age of individuals with a reported event was 24 years (range, 12-81 years). Of the reported cases, 207 (69.7%) occurred following the second dose of the COVID-19 mRNA vaccine. When restricted to individuals who received their second dose during the period of enhanced passive surveillance (on or after June 1, 2021), the highest rate of myocarditis or pericarditis was observed in male individuals aged 18 to 24 years following mRNA-1273 as the second dose (299.5 cases per 1 000 000 doses; 95% CI, 171.2-486.4 cases per 1 000 000 doses); the rate following BNT162b2 as the second dose was 59.2 cases per 1 000 000 doses (95% CI, 19.2-138.1 cases per 1 000 000 doses). Overall rates for both vaccine products were significantly higher when the interdose interval was 30 or fewer days (BNT162b2: 52.1 cases per 1 000 000 doses [95% CI, 31.8-80.5 cases per 1 000 000 doses]; mRNA-1273: 83.9 cases per 1 000 000 doses [95% CI, 47.0-138.4 cases per 1 000 000 doses]) compared with 56 or more days (BNT162b2: 9.6 cases per 1 000 000 doses [95% CI, 6.5-13.6 cases per 1 000 000 doses]; mRNA-1273: 16.2 cases per 1 000 000 doses [95% CI, 10.2-24.6 cases per 1 000 000 doses]). Conclusions and relevance: The findings of this population-based cohort study of Ontario adolescents and adults with myocarditis or pericarditis following mRNA COVID-19 vaccination suggest that vaccine products and interdose intervals, in addition to age and sex, may be associated with the risk of myocarditis or pericarditis after receipt of these vaccines. Vaccination program strategies, such as age-based product considerations and longer interdose intervals, may reduce the risk of myocarditis or pericarditis following receipt of mRNA vaccines.
  • Seasonality, Timing, and Climate Drivers of Influenza Activity Worldwide

    Azziz Baumgartner, Eduardo; Dao, Christine N.; Nasreen, Sharifa; Bhuiyan, Mejbah Uddin; Mah-E-Muneer, Syeda; Mamun, Abdullah Al; Sharker, M. A. Yushuf; Zaman, Rashid Uz; Cheng, Po-Yung; Klimov, Alexander I.; et al. (Oxford University Press (OUP), 2012-07-24)
    Background: Although influenza is a vaccine-preventable disease that annually causes substantial disease burden, data on virus activity in tropical countries are limited. We analyzed publicly available influenza data to better understand the global circulation of influenza viruses. Method: We reviewed open-source, laboratory-confirmed influenza surveillance data. For each country, we abstracted data on the percentage of samples testing positive for influenza each epidemiologic week from the annual number of samples testing positive for influenza. The start of influenza season was defined as the first week when the proportion of samples that tested positive remained above the annual mean. We assessed the relationship between percentage of samples testing positive and mean monthly temperature with use of regression models. Findings: We identified data on laboratory-confirmed influenza virus infection from 85 countries. More than one influenza epidemic period per year was more common in tropical countries (41%) than in temperate countries (15%). Year-round activity (ie, influenza virus identified each week having ≥ 10 specimens submitted) occurred in 3 (7%) of 43 temperate, 1 (17%) of 6 subtropical, and 11 (37%) of 30 tropical countries with available data (P = .006). Percentage positivity was associated with low temperature (P = .001). Interpretation: Annual influenza epidemics occur in consistent temporal patterns depending on climate.
  • Estimated Effectiveness of COVID-19 Vaccines Against Omicron or Delta Symptomatic Infection and Severe Outcomes

    Buchan, Sarah A.; Chung, Hannah; Brown, Kevin A.; Austin, Peter C.; Fell, Deshayne B.; Gubbay, Jonathan B.; Nasreen, Sharifa; Schwartz, Kevin L.; Sundaram, Maria E.; Tadrous, Mina; et al. (American Medical Association (AMA), 2022-09-22)
    Importance: The incidence of SARS-CoV-2 infection, including among individuals who have received 2 doses of COVID-19 vaccine, increased substantially following the emergence of the Omicron variant in Ontario, Canada. Understanding the estimated effectiveness of 2 or 3 doses of COVID-19 vaccine against outcomes associated with Omicron and Delta infections may aid decision-making at the individual and population levels. Objective: To estimate vaccine effectiveness (VE) against symptomatic infections due to the Omicron and Delta variants and severe outcomes (hospitalization or death) associated with these infections. Design, setting, and participants: This test-negative case-control study used linked provincial databases for SARS-CoV-2 laboratory testing, reportable disease, COVID-19 vaccination, and health administration in Ontario, Canada. Participants were individuals aged 18 years or older who had COVID-19 symptoms or severe outcomes (hospitalization or death) and were tested for SARS-CoV-2 between December 6 and 26, 2021. Exposures: Receipt of 2 or 3 doses of the COVID-19 vaccine and time since last dose. Main outcomes and measures: The main outcomes were symptomatic Omicron or Delta infection and severe outcomes (hospitalization or death) associated with infection. Multivariable logistic regression was used to estimate the effectiveness of 2 or 3 COVID-19 vaccine doses by time since the latest dose compared with no vaccination. Estimated VE was calculated using the formula VE = (1 - [adjusted odds ratio]) × 100%. Results: Of 134 435 total participants, 16 087 were Omicron-positive cases (mean [SD] age, 36.0 [14.1] years; 8249 [51.3%] female), 4261 were Delta-positive cases (mean [SD] age, 44.2 [16.8] years; 2199 [51.6%] female), and 114 087 were test-negative controls (mean [SD] age, 42.0 [16.5] years; 67 884 [59.5%] female). Estimated VE against symptomatic Delta infection decreased from 89% (95% CI, 86%-92%) 7 to 59 days after a second dose to 80% (95% CI, 74%-84%) after 240 or more days but increased to 97% (95% CI, 96%-98%) 7 or more days after a third dose. Estimated VE against symptomatic Omicron infection was 36% (95% CI, 24%-45%) 7 to 59 days after a second dose and 1% (95% CI, -8% to 10%) after 180 days or longer, but 7 or more days after a third dose, it increased to 61% (95% CI, 56%-65%). Estimated VE against severe outcomes was high 7 or more days after a third dose for both Delta (99%; 95% CI, 98%-99%) and Omicron (95%; 95% CI, 87%-98%). Conclusions and relevance: In this study, in contrast to high estimated VE against symptomatic Delta infection and severe outcomes after 2 doses of COVID-19 vaccine, estimated VE was modest and short term against symptomatic Omicron infection but better maintained against severe outcomes. A third dose was associated with improved estimated VE against symptomatic infection and with high estimated VE against severe outcomes for both variants. Preventing infection due to Omicron and potential future variants may require tools beyond the currently available vaccines.

View more