Efectividad del primer componente de (Sputnik V) en la reducción de infecciones confirmadas por SARS-CoV-2, hospitalizaciones y mortalidad en pacient

Effectiveness of the first component of Gam-COVID-Vac (Sputnik V) on reduction of SARS-CoV-2 confirmed infections, hospitalisations and mortality in patients aged 60-79: a retrospective cohort study in Argentina
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Background: A first-dose of various vaccines provides acceptable protection against infections by SARS-CoV-2
and evolution to the most severe forms of COVID-19. The recombinant adenovirus (rAd)-based vaccine,
Gam-COVID-Vac (Sputnik V), was proven efficacious but information about effectiveness in the real-world setting is lacking. The aim of our study was to investigate the association between the rollout of the first com-
ponent (rAd26) of Gam-COVID-Vac and PCR-positive tests, hospitalisations and deaths.

Methods: We conducted a retrospective cohort study which analyzed individuals aged 60-79 who self-regis-
tered in the online vaccination system of the Province of Buenos Aires, Argentina, from December 29, 2020 to March 21, 2021. Exclusion criteria were having a previous positive RT-PCR or antigen tests for SARS-CoV-
2, having received other vaccines, or two doses of any vaccine.

Proportions of new laboratory-confirmed SARS-CoV-2 infections, hospitalisations and deaths until 83 days of
vaccination were compared between vaccinated and unvaccinated subjects. Vaccine effectiveness for the
three outcomes was calculated as (1OR) £ 100. Kaplan-Meier cumulative incidence curves were
constructed.

Findings: During the study period 415995 registered subjects received the first component of Gam-COVID-
Vac; 40387 belonged to the 60-79 age group, and were compared to 38978 unvaccinated. Vaccine effective-
ness for preventing laboratory-confirmed infections was 786% [CI95% 74¢8 - 81¢7]; and for reducing hospital-
izations and deaths was, respectively, 87¢6% [CI95% 80¢3 - 92¢2] and 84¢8% [CI95% 75¢0 - 90¢7].
Effectiveness was high across all subgroups.

Interpretation: Similarly to other vaccines, the administration of one dose of Gam-COVID-Vac was effective
for a wide range of COVID-19related outcomes.
Funding: This study did not receive any funding.
© 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license