ABSTRACT
BACKGROUND: Beginning in March 2021, Mexico vaccinated childcare workers with a single-dose CanSino Biologics (Adv5-nCoV) coronavirus disease 2019 (COVID-19) vaccine. Although CanSino is currently approved for use in 10 Latin American, Asian, and European countries, little information is available about its vaccine effectiveness (VE). METHODS: We evaluated CanSino VE within a childcare worker cohort that included 1408 childcare facilities. Participants were followed during March-December 2021 and tested through severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse-transcription polymerase chain reaction or rapid antigen test if they developed any symptom compatible with COVID-19. Vaccination status was obtained through worker registries. VE was calculated as 100% × (1 - hazard ratio for SARS-CoV-2 infection in fully vaccinated vs unvaccinated participants), using an Andersen-Gill model adjusted for age, sex, state, and local viral circulation. RESULTS: The cohort included 43 925 persons who were mostly (96%) female with a median age of 32 years; 37 646 (86%) were vaccinated with CanSino. During March-December 2021, 2250 (5%) participants had laboratory-confirmed COVID-19, of whom 25 were hospitalized and 6 died. Adjusted VE was 20% (95% confidence interval [CI], 10%-29%) against illness, 76% (95% CI, 42%-90%) against hospitalization, and 94% (95% CI, 66%-99%) against death. VE against illness declined from 48% (95% CI, 33%-61%) after 14-60 days following full vaccination to 20% (95% CI, 9%-31%) after 61-120 days. CONCLUSIONS: CanSino vaccine was effective at preventing COVID-19 illness and highly effective at preventing hospitalization and death. It will be useful to further evaluate duration of protection and assess the value of booster doses to prevent COVID-19 and severe outcomes.
Subject(s)
COVID-19 Vaccines , COVID-19 , Adult , COVID-19/prevention & control , Child , Child Care , Female , Humans , Male , Mexico/epidemiology , SARS-CoV-2 , Vaccine EfficacyABSTRACT
OBJECTIVE: To describe the epidemiology and risk factors for hospitalisation and death in Mexican children under 18 years of age with COVID-19. DESIGN: Retrospective, cross-sectional and analytical study. SETTING: Mexican Ministry of Health open databases with COVID-19 cases occurred from 7 March 2020 to 30 September 2021. PARTICIPANTS: Mexican children under 18 years of age with COVID-19. MAIN OUTCOME MEASURES: COVID-19 hospitalisations and deaths were characterised by age group, sex, presence of pneumonia and comorbidities, intubation and intensive care unit admission, and institution that provided medical care. Cumulative incidence, mortality, case fatality rates and ORs for hospitalisation and death were estimated by age group. RESULTS: 5.5% (204 641) of national COVID-19 cases were children under 18 years of age: 2.9% under 1 year, 12.5% from 1 to 5 years, 15% from 6 to 9 years and 69.4% from 10 to 17 years. 4.6% of all cases were hospitalised, from which 54.6% were male, 35.3% were children under 1 year old, 39.6% were adolescents and 34% had pneumonia. Pneumonia developed in 2.3% of cases, from which 50% were adolescents. Case fatality rate was higher in children less than 1 year old (4.2%). Risk analyses showed that male sex (OR 1.16-1.28), history of pneumonia (OR 29.7-65.4), immunosuppression (OR 5.3-42.9), cardiovascular disease (OR 4.4-14.6) and other comorbidities (OR 5.4-19.1), as well as age less than 1 year (OR 20.1, 95% CI 18.8 to 21.4), confer a greater risk of hospitalisation; in addition to comorbidities, age less than 1 year (OR 16.6, 95% CI 14.1 to 19.6), history of pneumonia (OR 14.1-135.1) and being an adolescent from an indigenous community (OR 2.6, 95% CI 1.23 to 5.54, p=0.012) increase the risk of death. CONCLUSIONS: In Mexico, children less than 1 year old with COVID-19 have higher risk of hospitalisation and death than older children. Adolescents with COVID-19 in association with comorbidities develop adverse outcomes more frequently.