TY - JOUR
T1 - Maternal Vaccination and Risk of Hospitalization for Covid-19 among Infants
AU - Halasa, Natasha B.
AU - Olson, Samantha M.
AU - Staat, Mary A.
AU - Newhams, Margaret M.
AU - Price, Ashley M.
AU - Pannaraj, Pia S.
AU - Boom, Julie A.
AU - Sahni, Leila C.
AU - Chiotos, Kathleen
AU - Cameron, Melissa A.
AU - Bline, Katherine E.
AU - Hobbs, Charlotte V.
AU - Maddux, Aline B.
AU - Coates, Bria M.
AU - Michelson, Kelly N.
AU - Heidemann, Sabrina M.
AU - Irby, Katherine
AU - Nofziger, Ryan A.
AU - Mack, Elizabeth H.
AU - Smallcomb, Laura
AU - Schwartz, Stephanie P.
AU - Walker, Tracie C.
AU - Gertz, Shira J.
AU - Schuster, Jennifer E.
AU - Kamidani, Satoshi
AU - Tarquinio, Keiko M.
AU - Bhumbra, Samina S.
AU - Maamari, Mia
AU - Hume, Janet R.
AU - Crandall, Hillary
AU - Levy, Emily R.
AU - Zinter, Matt S.
AU - Bradford, Tamara T.
AU - Flori, Heidi R.
AU - Cullimore, Melissa L.
AU - Kong, Michele
AU - Cvijanovich, Natalie Z.
AU - Gilboa, Suzanne M.
AU - Polen, Kara N.
AU - Campbell, Angela P.
AU - Randolph, Adrienne G.
AU - Patel, Manish M.
N1 - Publisher Copyright:
Copyright © 2022 Massachusetts Medical Society.
PY - 2022/7/14
Y1 - 2022/7/14
N2 - Infants younger than 6 months of age are at high risk for complications of coronavirus disease 2019 (Covid-19) and are not eligible for vaccination. Transplacental transfer of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after maternal Covid-19 vaccination may confer protection against Covid-19 in infants. METHODS We used a case–control test-negative design to assess the effectiveness of maternal vaccination during pregnancy against hospitalization for Covid-19 among infants younger than 6 months of age. Between July 1, 2021, and March 8, 2022, we enrolled infants hospitalized for Covid-19 (case infants) and infants hospitalized without Covid-19 (control infants) at 30 hospitals in 22 states. We estimated vaccine effectiveness by comparing the odds of full maternal vaccination (two doses of mRNA vaccine) among case infants and control infants during circulation of the B.1.617.2 (delta) variant (July 1, 2021, to December 18, 2021) and the B.1.1.259 (omicron) variant (December 19, 2021, to March 8, 2022). RESULTS A total of 537 case infants (181 of whom had been admitted to a hospital during the delta period and 356 during the omicron period; median age, 2 months) and 512 control infants were enrolled and included in the analyses; 16% of the case infants and 29% of the control infants had been born to mothers who had been fully vaccinated against Covid-19 during pregnancy. Among the case infants, 113 (21%) received intensive care (64 [12%] received mechanical ventilation or vasoactive infusions). Two case infants died from Covid-19; neither infant’s mother had been vaccinated during pregnancy. The effectiveness of maternal vaccination against hospitalization for Covid-19 among infants was 52% (95% confidence interval [CI], 33 to 65) overall, 80% (95% CI, 60 to 90) during the delta period, and 38% (95% CI, 8 to 58) during the omicron period. Effectiveness was 69% (95% CI, 50 to 80) when maternal vaccination occurred after 20 weeks of pregnancy and 38% (95% CI, 3 to 60) during the first 20 weeks of pregnancy. CONCLUSIONS Maternal vaccination with two doses of mRNA vaccine was associated with a reduced risk of hospitalization for Covid-19, including for critical illness, among infants younger than 6 months of age.
AB - Infants younger than 6 months of age are at high risk for complications of coronavirus disease 2019 (Covid-19) and are not eligible for vaccination. Transplacental transfer of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after maternal Covid-19 vaccination may confer protection against Covid-19 in infants. METHODS We used a case–control test-negative design to assess the effectiveness of maternal vaccination during pregnancy against hospitalization for Covid-19 among infants younger than 6 months of age. Between July 1, 2021, and March 8, 2022, we enrolled infants hospitalized for Covid-19 (case infants) and infants hospitalized without Covid-19 (control infants) at 30 hospitals in 22 states. We estimated vaccine effectiveness by comparing the odds of full maternal vaccination (two doses of mRNA vaccine) among case infants and control infants during circulation of the B.1.617.2 (delta) variant (July 1, 2021, to December 18, 2021) and the B.1.1.259 (omicron) variant (December 19, 2021, to March 8, 2022). RESULTS A total of 537 case infants (181 of whom had been admitted to a hospital during the delta period and 356 during the omicron period; median age, 2 months) and 512 control infants were enrolled and included in the analyses; 16% of the case infants and 29% of the control infants had been born to mothers who had been fully vaccinated against Covid-19 during pregnancy. Among the case infants, 113 (21%) received intensive care (64 [12%] received mechanical ventilation or vasoactive infusions). Two case infants died from Covid-19; neither infant’s mother had been vaccinated during pregnancy. The effectiveness of maternal vaccination against hospitalization for Covid-19 among infants was 52% (95% confidence interval [CI], 33 to 65) overall, 80% (95% CI, 60 to 90) during the delta period, and 38% (95% CI, 8 to 58) during the omicron period. Effectiveness was 69% (95% CI, 50 to 80) when maternal vaccination occurred after 20 weeks of pregnancy and 38% (95% CI, 3 to 60) during the first 20 weeks of pregnancy. CONCLUSIONS Maternal vaccination with two doses of mRNA vaccine was associated with a reduced risk of hospitalization for Covid-19, including for critical illness, among infants younger than 6 months of age.
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U2 - 10.1056/NEJMoa2204399
DO - 10.1056/NEJMoa2204399
M3 - Article
C2 - 35731908
AN - SCOPUS:85133679555
SN - 0028-4793
VL - 387
SP - 109
EP - 119
JO - New England Journal of Medicine
JF - New England Journal of Medicine
IS - 2
ER -