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. 2021 Oct:40:101126.
doi: 10.1016/j.eclinm.2021.101126. Epub 2021 Sep 12.

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

Soledad González  1 , Santiago Olszevicki  1 , Martín Salazar  2 , Ana Calabria  1 , Lorena Regairaz  3 , Lupe Marín  1 , Patricia Campos  1 , Teresa Varela  1 , Veronica V González Martínez  1 , Leticia Ceriani  1 , Enio Garcia  1 , Nicolás Kreplak  1 , Marina Pifano  1 , Elisa Estenssoro  1 , Franco Marsico  4
Affiliations

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

Soledad González et al. EClinicalMedicine. 2021 Oct.

Abstract

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 component (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-registered 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 (1-OR) × 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 effectiveness for preventing laboratory-confirmed infections was 78•6% [CI95% 74·8 - 81·7]; and for reducing hospitalizations 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-19-related outcomes.

Funding: This study did not receive any funding.

Keywords: Immunization; covid-19; infectious diseases; vaccination.

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Conflict of interest statement

NK, LC, TV and PC declared being involved in the decision making process of the vaccination campaign in the Province of Buenos Aires, Argentina. All other authors report no competing interests.

Figures

Figure 1
Figure 1
Flowchart of the study.
Figure 2
Figure 2
For 60 to 79 matched group, distribution between vaccinated and unvaccinated individuals for age (Panel A); gender (F, female; M, Male) (Panel B); presence of comorbidity (Panel C); vaccination date and follow-update for the unvaccinated) (Panel D); and distribution of the exposure time (Panel E). Error bars indicate the %[CI95%].
Figure 3
Figure 3
Vaccine effectiveness for different categories: 60-69 and 70-79 age subgroups, Females (F), Males (M), individuals with comorbidities (C) and without them (NC), between days 21 and 40 of follow-up days. Laboratory confirmed cases include asymptomatic infections by SARS-CoV2 and symptomatic infections (COVID-19). Error bars indicate the %[CI95%].
Figure 4
Figure 4
Cumulative incidence of laboratory confirmed-cases, hospitalisations and deaths for vaccinated and unvaccinated (matched) groups. Laboratory confirmed cases include asymptomatic infections by SARS-CoV2 and symptomatic infections (COVID-19). Error bars indicate the %[CI95%].
See this image and copyright information in PMC

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