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Bolotin S, Hughes SL, Savage RD, McLachlan E, Severini A, Arnold C, Richardson S, Crowcroft NS, Deek S, Halperin SA, Brown KA, Hatchette T, Osman S, Gubbay JB, Science M. Maternal varicella antibodies in children aged less than one year: Assessment of antibody decay. PLoS One 2023; 18:e0287765. [PMID: 37948389 PMCID: PMC10637651 DOI: 10.1371/journal.pone.0287765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 06/13/2023] [Indexed: 11/12/2023] Open
Abstract
OBJECTIVES To investigate maternal antibody levels to varicella in infants <12 months of age in Ontario, Canada. STUDY DESIGN In this study, we included specimens from infants <12 months of age, born at ≥37 weeks gestational age, who had sera collected at The Hospital for Sick Children (Toronto, Canada) between 2014-2016. We tested sera using a glycoprotein-based enzyme-linked immunosorbent assay (gpELISA). We measured varicella susceptibility (antibody concentration <150mIU/mL) and mean varicella antibody concentration, and assessed the probability of susceptibility and concentration between one and 11 months of age using multivariable logistic regression and Poisson regression. RESULTS We found that 32% of 196 included specimens represented infants susceptible to varicella at one month of age, increasing to nearly 80% at three months of age. At six months of age, all infants were susceptible to varicella and the predicted mean varicella antibody concentration declined to 62 mIU/mL (95% confidence interval 40, 84), well below the threshold of protection. CONCLUSIONS We found that varicella maternal antibody levels wane rapidly in infants, leaving most infants susceptible by four months of age. Our findings have implications for the timing of first dose of varicella-containing vaccine, infection control measures, and infant post-exposure prophylaxis recommendations.
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Affiliation(s)
- Shelly Bolotin
- Public Health Ontario, Toronto, Ontario, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
- Centre for Vaccine Preventable Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | | | - Rachel D. Savage
- Public Health Ontario, Toronto, Ontario, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Elizabeth McLachlan
- National Microbiology Laboratory, Public Health Agency of Canada, Ottawa, Ontario, Canada
- Department of Medical Microbiology, University of Manitoba, Manitoba, Canada
| | - Alberto Severini
- National Microbiology Laboratory, Public Health Agency of Canada, Ottawa, Ontario, Canada
- Department of Medical Microbiology, University of Manitoba, Manitoba, Canada
| | - Callum Arnold
- Division of Infectious Diseases, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Susan Richardson
- Division of Microbiology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Natasha S. Crowcroft
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
- Centre for Vaccine Preventable Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- Department of Immunization, Vaccines & Biologicals, World Helath Organization, Geneva, Switzerland
| | - Shelley Deek
- Public Health Ontario, Toronto, Ontario, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Scott A. Halperin
- Canadian Center for Vaccinology (CCfV), IWK Health Centre, Nova Scotia Health (NSH), and Dalhousie University, Halifax, Nova Scotia (NS), Canada
| | - Kevin A. Brown
- Public Health Ontario, Toronto, Ontario, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Todd Hatchette
- Canadian Center for Vaccinology (CCfV), IWK Health Centre, Nova Scotia Health (NSH), and Dalhousie University, Halifax, Nova Scotia (NS), Canada
| | - Selma Osman
- Public Health Ontario, Toronto, Ontario, Canada
| | - Jonathan B. Gubbay
- Public Health Ontario, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- Division of Infectious Diseases, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Michelle Science
- Public Health Ontario, Toronto, Ontario, Canada
- Division of Infectious Diseases, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
- Department of Paediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
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Bianchi FP, Tafuri S, Larocca AMV, Germinario CA, Stefanizzi P. Long -term persistence of antibodies against varicella in fully immunized healthcare workers: an Italian retrospective cohort study. BMC Infect Dis 2021; 21:475. [PMID: 34034659 PMCID: PMC8152326 DOI: 10.1186/s12879-021-06180-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 05/12/2021] [Indexed: 12/12/2022] Open
Abstract
Background Chickenpox is a highly contagious disease caused by the varicella zoster virus (VZV), and in infants, adolescents, adults, pregnant women, and the immunocompromised it can be serious. The best way to prevent chickenpox is immunization with the varicella vaccine. Protective levels of antibodies induced by the varicella vaccine decline over time, but there is currently no formal recommendation for testing anti-varicella zoster virus (VZV) IgG levels in immunized healthcare workers (HCWs). Methods The aims of this study were to evaluate the seroprevalence of circulating anti-VZV IgG in a sample a sample of students and residents of the medical school of the University of Bari, the long-term immunogenicity of the varicella vaccine, and the effectiveness of a strategy consisting of a third vaccine booster dose. The study population was screened as part of a biological risk assessment conducted between April 2014 and October 2020. A strategy for the management of non-responders was also examined. Results The 182 students and residents included in the study had a documented history of immunization (two doses of varicella vaccine). The absence of anti-VZV IgG was determined in 34% (62/182; 95%CI = 27.2–41.4%), with serosusceptibility more common among males than females (p < 0.05). After a third varicella dose, seroconversion was achieved in 100% of this previously seronegative group. No serious adverse events were recorded. Conclusions One-third of the study population immunized against VZV lacked a protective antibody titer, but a third dose of vaccine restored protection. Since it is highly unlikely that VZV will be eliminated in the immediate future, the loss of immunity in a substantial portion of the population implies a risk of varicella outbreaks in the coming years. Screening for varicella immunity in routine assessments of the biological risk of medical students and HCWs may help to prevent nosocomial VZV infections.
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Affiliation(s)
- Francesco Paolo Bianchi
- Department of Biomedical Science and Human Oncology, Aldo Moro University of Bari, Piazza Giulio Cesare 11, 70124, Bari, Italy
| | - Silvio Tafuri
- Department of Biomedical Science and Human Oncology, Aldo Moro University of Bari, Piazza Giulio Cesare 11, 70124, Bari, Italy.
| | | | - Cinzia Annatea Germinario
- Department of Biomedical Science and Human Oncology, Aldo Moro University of Bari, Piazza Giulio Cesare 11, 70124, Bari, Italy
| | - Pasquale Stefanizzi
- Department of Biomedical Science and Human Oncology, Aldo Moro University of Bari, Piazza Giulio Cesare 11, 70124, Bari, Italy
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