RESUMEN

BACKGROUND: The BNT162b2 vaccine against coronavirus disease 2019 (Covid-19) has been authorized for use in children 5 to 11 years of age and adolescents 12 to 17 years of age but in different antigen doses. METHODS: We assessed the real-world effectiveness of the BNT162b2 vaccine against infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among children and adolescents in Qatar. To compare the incidence of SARS-CoV-2 infection in the national cohort of vaccinated participants with the incidence in the national cohort of unvaccinated participants, we conducted three matched, retrospective, target-trial, cohort studies - one assessing data obtained from children 5 to 11 years of age after the B.1.1.529 (omicron) variant became prevalent and two assessing data from adolescents 12 to 17 years of age before the emergence of the omicron variant (pre-omicron study) and after the omicron variant became prevalent. Associations were estimated with the use of Cox proportional-hazards regression models. RESULTS: Among children, the overall effectiveness of the 10-µg primary vaccine series against infection with the omicron variant was 25.7% (95% confidence interval [CI], 10.0 to 38.6). Effectiveness was highest (49.6%; 95% CI, 28.5 to 64.5) right after receipt of the second dose but waned rapidly thereafter and was negligible after 3 months. Effectiveness was 46.3% (95% CI, 21.5 to 63.3) among children 5 to 7 years of age and 16.6% (95% CI, -4.2 to 33.2) among those 8 to 11 years of age. Among adolescents, the overall effectiveness of the 30-µg primary vaccine series against infection with the omicron variant was 30.6% (95% CI, 26.9 to 34.1), but many adolescents had been vaccinated months earlier. Effectiveness waned over time since receipt of the second dose. Effectiveness was 35.6% (95% CI, 31.2 to 39.6) among adolescents 12 to 14 years of age and 20.9% (95% CI, 13.8 to 27.4) among those 15 to 17 years of age. In the pre-omicron study, the overall effectiveness of the 30-µg primary vaccine series against SARS-CoV-2 infection among adolescents was 87.6% (95% CI, 84.0 to 90.4) and waned relatively slowly after receipt of the second dose. CONCLUSIONS: Vaccination in children was associated with modest, rapidly waning protection against omicron infection. Vaccination in adolescents was associated with stronger, more durable protection, perhaps because of the larger antigen dose. (Funded by Weill Cornell Medicine-Qatar and others.).

Asunto(s)

Vacuna BNT162 , COVID-19 , Eficacia de las Vacunas , Adolescente , Niño , Humanos , Vacuna BNT162/administración & dosificación , Vacuna BNT162/uso terapéutico , COVID-19/epidemiología , COVID-19/prevención & control , Vacunas contra la COVID-19/administración & dosificación , Vacunas contra la COVID-19/uso terapéutico , Qatar/epidemiología , Estudios Retrospectivos , SARS-CoV-2 , Preescolar , Eficacia de las Vacunas/estadística & datos numéricos

RESUMEN

Background The Zika virus has become an international health issue and poses a systematic risk for a growing number of travelers. Qatar is no exception to this status, where its Hamad International Airport (HIA) has become an important hub for many travelers to and from affected countries. Thus, it is a national necessity to determine the knowledge, attitude, and practice of travelers' regarding this emerging disease in the State of Qatar. Methods This was a cross-sectional study that employed a self-administered questionnaire (n=100) and was conducted at Hamad International Airport. Descriptive and inferential statistical tests were applied to analyze the data using the Statistical Package for the Social Sciences (SPSS) (IBM SPSS Statistics 21, IBM Corporation, Armonk, NY, USA, 2014). Results The majority of travelers (75%) reported hearing about the Zika disease prior to their current flight, mainly from the media (73%) and the internet (46%). The majority of participants (69%) knew about the vector-borne transmission and symptomatology of a Zika infection while more than half (54%) correctly identified effective methods to prevent infection. Regarding their attitude, less than two-thirds (58%) of the participants agreed that pregnant women must postpone their travel to any Zika-affected area. Regarding their practice, only a quarter of the sampled travelers (24%) sought pre-travel medical advice before going to Brazil. Comparing the knowledge score among different education levels, we found that high-school students scored significantly better than those with diplomas and bachelors, p=0.042 and p=0.012, respectively. Conclusion The survey findings revealed that the knowledge of Zika infection is low among travelers to Brazil. Thus, stronger efforts to educate travelers about Zika are recommended. It is also vital that travelers be encouraged to seek proper medical advice prior to travel.