Waning Effectiveness of the BNT162b2 Vaccine Against Infection in Adolescents in Israel.
Clin Infect Dis
; 76(1): 113-118, 2023 01 06.
Article
in English
| MEDLINE | ID: covidwho-2160983
ABSTRACT
BACKGROUND:
The short-term effectiveness of a 2-dose regimen of the BioNTech/Pfizer BNT162b2 vaccine for adolescents has been demonstrated. However, little is known about the long-term effectiveness in this age group. It is known, however, that waning of vaccine-induced immunity against infection in adult populations is evident within a few months.METHODS:
Leveraging the database of Maccabi Healthcare Services (MHS), we conducted a matched case-control design for evaluating the association between time since vaccination and the incidence of infections, where 2 outcomes were evaluated documented SARS-CoV-2 infection (regardless of symptoms) and symptomatic infection (COVID-19). Cases were defined as individuals aged 12-16 with a positive polymerase chain reaction (PCR) test occurring between 15 June and 8 December 2021, when the Delta variant was dominant in Israel. Controls were adolescents who had not tested positive previously.RESULTS:
We estimated a peak vaccine effectiveness between 2 weeks and 3 months following receipt of the second dose, with 85% (95% confidence interval [CI] 84-86%) and 90% (95% CI 89-91%) effectiveness against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19), respectively. However, in line with findings for adults, waning effectiveness was evident. Long-term protection was reduced to 73% (95% CI 68-77%) against infection and 79% (95% CI 73-83%) against COVID-19 3-5 months after the second dose and waned to 53% (95% CI 46-60%) against infection and 66% (95% CI 59-72%) against COVID-19 after 5 months.CONCLUSIONS:
Although vaccine-induced protection against both infection and COVID-19 continues over time in adolescents, the protection wanes with time since vaccination, starting 3 months after inoculation and continuing for more than 5 months.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Vaccines
/
COVID-19
Type of study:
Experimental Studies
/
Observational study
Topics:
Long Covid
/
Vaccines
/
Variants
Limits:
Adolescent
/
Adult
/
Humans
Country/Region as subject:
Asia
Language:
English
Journal:
Clin Infect Dis
Journal subject:
Communicable Diseases
Year:
2023
Document Type:
Article
Affiliation country:
Cid
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