Dataset Information

The impact of COVID-19 vaccination program in the Republic of San Marino: focus on effectiveness of Gam-COVID-Vac.

ABSTRACT:

Objectives

The adenovirus-based vaccine Gam-COVID-Vac (Sputnik V), showed promising effectiveness in a phase 3 clinical trial; however, data concerning its impact at a population level are scarce. The Republic of San Marino (RSM) conducted a SARS-CoV-2 vaccination program mainly based (>80%) on Gam-COVID-Vac. Our aims were to investigate the impact of Gam-COVID-Vac vaccination program and its effectiveness in a retrospective observational study based on the entire RSM population aged 12 or older.

Methods

We calculated the incidence rate (IR) and the vaccine effectiveness (VE) in the entire RSM population not previously infected, against SARS-CoV-2 infection and COVID-19-related hospitalization, from 25^th February to 1^st October 2021, considering any vaccine and separately according to the vaccine used. Vaccine effectiveness was calculated using a multivariable negative binomial regression model as 1-Incidence Rate Ratio (IRR).

Results

During the study period, 21,568/28,791 (74.9%) not previously infected subjects received at least one dose of the Gam-COVID-Vac (84%) or BNT162b2, vaccines with 98% completing the vaccination schedule. Overall, 1,634 SARS-CoV-2 infections and 166 COVID-19-related hospitalizations were observed with 17 COVID-19-related deaths reported. IRs of SARS-CoV-2 infection and COVID-19-related hospitalization were 7.11 and 0.49/100,000 person-days (PDs) in the fully vaccinated population, respectively. Adjusted overall VE was 67.6% (95% CI: 61.8-72.5%) against SARS-CoV-2 infection, and 87.9% (95% CI: 77.4-93.5%) against COVID-19-related hospitalizations. Gam-COVID-Vac against SARS-CoV-2 infection VE peaked 91.8% (95% CI: 86.3-95.1%) in the first bimester from the second dose, declining to 57.8 % (95% CI: 42.2-69.2%) at six months. Protection against hospitalization with COVID-19 was overall 91.6% (95% CI: 81.5-96.2%), with no relevant waning trend over time.

Conclusions

Our study demonstrated the effectiveness of overall vaccination (Gam-COVID-Vac [84%] and BNT162b2 [16%]) in the prevention SARS-CoV-2 infection (pre-Omicron variant), waning over time but still with sustainable effectiveness against COVID-19-related hospitalization in the Republic of San Marino.

SUBMITTER: Tonnara G

PROVIDER: S-EPMC9251905 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundMonitoring vaccine effectiveness (VE) remains a priority for epidemiological research throughout the COVID-19 pandemic. VE against infection declines with the emergence of new SARS-CoV-2 variants of concern (VOC), but VE against the severe disease remains high. Therefore, we aimed to estimate the effectiveness of COVID-19 vaccines used in Russia against lung injury during Delta and Omicron VOC surges.MethodsWe designed a case-control study (test-negative design) to estimate VE against any (any volume of involved lung parenchyma) and severe (>50% of involved parenchyma) lung injury detected on computer tomography and associated with COVID-19 between October 1, 2021-April 28, 2022 (Delta VOC dominance period followed by Omicron dominance period). We included the data of patients with symptomatic confirmed SARS-CoV-2 infection referred to the low-dose computer tomography triage centres.ResultsAmong 23996 patients in the primary analysis, 13372 (55.7%) had any lung injury, and 338 (1.4%) had severe lung injury. The adjusted for age, sex and triage centre VE estimates against any lung injury were 56% (95% confidence interval 54-59) for two-dose Gam-COVID-Vac (Sputnik V), 71% (68-74) for three-dose Gam-COVID-Vac (booster), 2% (-27 to 24) for EpiVacCorona, and 46% (37-53) for CoviVac. VE estimates against severe lung injury were 76% (67-82) for two-dose Gam-COVID-Vac (Sputnik V), 87% (76-93) for three-dose Gam-COVID-Vac, 36% (-63 to 75) for EpiVacCorona, and 80% (45-92) for CoviVac.ConclusionsGam-COVID-Vac remained effective against lung injury associated with COVID-19 during Delta and Omicron VOC surges, and one Gam-COVID-Vac booster could be seen as an appropriate option after a two-dose regimen. CoviVac was also effective against lung injury. EpiVacCorona use in population-based vaccination should be halted until effectiveness and efficacy evidence is provided. Trial registration The joint study of COVID-19 vaccine effectiveness in St. Petersburg was registered at ClinicalTrials.gov (NCT04981405, date of registration-August 4, 2021).

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