Michelle Science1,2,3, Rachel Savage2,4, Alberto Severini5,6, Elizabeth McLachlan5, Stephanie L Hughes2, Callum Arnold7, Susan Richardson8, Natasha Crowcroft2,9,4,10, Shelley Deeks2,4, Scott Halperin11, Kevin Brown2,4,10, Todd Hatchette11, Jonathan Gubbay7,2,3,9, Tony Mazzulli2,9,12, Shelly Bolotin13,9,4. 1. Division of Infectious Diseases, Department of Paediatrics, and michelle.science@sickkids.ca. 2. Public Health Ontario, Toronto, Ontario, Canada. 3. Departments of Paediatrics and. 4. Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada. 5. National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada. 6. Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada. 7. Division of Infectious Diseases, Department of Paediatrics, and. 8. Division of Microbiology, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada. 9. Laboratory Medicine and Pathobiology, University of Toronto, Toronto Canada. 10. ICES, Toronto, Ontario, Canada. 11. Canadian Center for Vaccinology (CCfV), IWK Health Centre, Nova Scotia Health Authority (NSHA), and Dalhousie University, Halifax, Nova Scotia (NS), Canada; and. 12. Mount Sinai Hospital, University Health Network, Toronto, Ontario, Canada. 13. Public Health Ontario, Toronto, Ontario, Canada; michelle.science@sickkids.ca.
Abstract
BACKGROUND: Infants are often assumed to be immune to measles through maternal antibodies transferred during pregnancy and, in many countries, receive their first measles-containing vaccine at 12 to 15 months. Immunity may wane before this time in measles-eliminated settings, placing infants at risk for measles and complications. We investigated humoral immunity to measles in infants <12 months of age in Ontario, Canada. METHODS: We selected sera collected at a tertiary pediatric hospital from infants <12 months who were born at ≥37 weeks' gestational age. We excluded infants with conditions that affect antibody levels. We selected ≤25 sera from 8 predetermined age bands and tested them for measles-neutralizing antibody using the plaque-reduction neutralization test. We calculated the proportion immune at each age band, and predictors of infant susceptibility were assessed by using multivariable logistic regression and Poisson regression. RESULTS: Of 196 infant sera, 56% (110 of 196) were from boys, and 35% (69 of 196) were from infants with underlying medical conditions. In the first month, 20% (5 of 25) of infants had antibodies below the protective threshold, which increased to 92% (22 of 24) by 3 months. By 6 months, all infants had titers below the protective threshold. In a multivariable analysis, infant age was the strongest predictor of susceptibility (odds ratio = 2.13 for each additional month increase; 95% confidence interval: 1.52-2.97). CONCLUSIONS: Most infants were susceptible to measles by 3 months of age in this elimination setting. Our findings inform important policy discussions relating to the timing of the first dose of measles-containing vaccine and infant postexposure prophylaxis recommendations.
BACKGROUND:Infants are often assumed to be immune to measles through maternal antibodies transferred during pregnancy and, in many countries, receive their first measles-containing vaccine at 12 to 15 months. Immunity may wane before this time in measles-eliminated settings, placing infants at risk for measles and complications. We investigated humoral immunity to measles in infants <12 months of age in Ontario, Canada. METHODS: We selected sera collected at a tertiary pediatric hospital from infants <12 months who were born at ≥37 weeks' gestational age. We excluded infants with conditions that affect antibody levels. We selected ≤25 sera from 8 predetermined age bands and tested them for measles-neutralizing antibody using the plaque-reduction neutralization test. We calculated the proportion immune at each age band, and predictors of infant susceptibility were assessed by using multivariable logistic regression and Poisson regression. RESULTS: Of 196 infant sera, 56% (110 of 196) were from boys, and 35% (69 of 196) were from infants with underlying medical conditions. In the first month, 20% (5 of 25) of infants had antibodies below the protective threshold, which increased to 92% (22 of 24) by 3 months. By 6 months, all infants had titers below the protective threshold. In a multivariable analysis, infant age was the strongest predictor of susceptibility (odds ratio = 2.13 for each additional month increase; 95% confidence interval: 1.52-2.97). CONCLUSIONS: Most infants were susceptible to measles by 3 months of age in this elimination setting. Our findings inform important policy discussions relating to the timing of the first dose of measles-containing vaccine and infant postexposure prophylaxis recommendations.
Authors: Fleurette M Domai; Kristal An Agrupis; Su Myat Han; Ana Ria Sayo; Janine S Ramirez; Raphael Nepomuceno; Shuichi Suzuki; Annavi Marie G Villanueva; Eumelia P Salva; Jose Benito Villarama; Koya Ariyoshi; Kim Mulholland; Luigi Palla; Kensuke Takahashi; Chris Smith; Edna Miranda Journal: Lancet Reg Health West Pac Date: 2021-12-15
Authors: Benno Kohlmaier; Heidemarie Holzmann; Karin Stiasny; Manuel Leitner; Christoph Zurl; Volker Strenger; Michael Kundi; Werner Zenz Journal: Front Pediatr Date: 2021-12-02 Impact factor: 3.418