Effectiveness of the CoronaVac vaccine in older adults during a gamma variant associated epidemic of covid-19 in Brazil: test negative case-control study

OT Ranzani, MDT Hitchings, M Dorion, TL D'Agostini… - bmj, 2021 - bmj.com
Objective To estimate the effectiveness of the inactivated whole virus vaccine, CoronaVac
(Sinovac Biotech), against symptomatic covid-19 in the elderly population of São Paulo …

Effectiveness of BNT162b2 and mRNA-1273 covid-19 vaccines against symptomatic SARS-CoV-2 infection and severe covid-19 outcomes in Ontario, Canada: test …

H Chung, S He, S Nasreen, ME Sundaram, SA Buchan… - bmj, 2021 - bmj.com
Objective To estimate the effectiveness of mRNA covid-19 vaccines against symptomatic
infection and severe outcomes (hospital admission or death). Design Test negative design …

Waning of vaccine effectiveness against moderate and severe covid-19 among adults in the US from the VISION network: test negative, case-control study

JM Ferdinands, S Rao, BE Dixon, PK Mitchell… - Bmj, 2022 - bmj.com
Objective To estimate the effectiveness of mRNA vaccines against moderate and severe
covid-19 in adults by time since second, third, or fourth doses, and by age and …

Effectiveness of an inactivated Covid-19 vaccine with homologous and heterologous boosters against Omicron in Brazil

OT Ranzani, MDT Hitchings, RL de Melo… - Nature …, 2022 - nature.com
The effectiveness of inactivated vaccines (VE) against symptomatic and severe COVID-19
caused by omicron is unknown. We conducted a nationwide, test-negative, case-control …

Effectiveness of ChAdOx1 vaccine in older adults during SARS-CoV-2 Gamma variant circulation in São Paulo

MDT Hitchings, OT Ranzani, M Dorion… - Nature …, 2021 - nature.com
A two-dose regimen of the Oxford-AstraZeneca (ChAdOx1) Covid-19 vaccine with an inter-
dose interval of three months has been implemented in many countries with restricted …

Influence of age on the effectiveness and duration of protection of Vaxzevria and CoronaVac vaccines: A population-based study

T Cerqueira-Silva, V de Araújo Oliveira… - The Lancet Regional …, 2022 - thelancet.com
Background Aging influences COVID-19 severity and response to vaccination, but previous
vaccine effectiveness (VE) analyzes lack the power to evaluate its role in subgroups within …

Effectiveness of CoronaVac, ChAdOx1 nCoV-19, BNT162b2, and Ad26. COV2. S among individuals with previous SARS-CoV-2 infection in Brazil: a test-negative …

T Cerqueira-Silva, JR Andrews… - The Lancet Infectious …, 2022 - thelancet.com
Background COVID-19 vaccines have proven highly effective among individuals without a
previous SARS-CoV-2 infection, but their effectiveness in preventing symptomatic infection …

[HTML][HTML] Effectiveness of BBV152/Covaxin and AZD1222/Covishield vaccines against severe COVID-19 and B. 1.617. 2/Delta variant in India, 2021: a multi-centric …

T Bhatnagar, S Chaudhuri, M Ponnaiah… - International Journal of …, 2022 - Elsevier
Abstract Objectives India introduced BBV152/Covaxin and AZD1222/Covishield vaccines in
January 2021. We estimated the effectiveness of these vaccines against severe COVID-19 …

Biases in COVID-19 vaccine effectiveness studies using cohort design

S Agampodi, BT Tadesse, S Sahastrabuddhe… - Frontiers in …, 2024 - frontiersin.org
Observational studies on COVID-19 vaccine effectiveness (VE) have provided critical real-
world data, informing public health policy globally. These studies, primarily using pre …

Effectiveness of the fourth dose of COVID-19 vaccines against severe COVID-19 among adults 40 years or older in Brazil: a population-based cohort study

FL Neto, MDT Hitchings, AB Amin… - The Lancet Regional …, 2024 - thelancet.com
Background The emergence of COVID-19 variants with immune scape and the waning of
primary vaccine schemes effectiveness have prompted many countries to indicate first and …