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Vaccination impact: mortality and time shift to COVID-19 maximum severity in hospitalized patients. An Argentine
Matias Mirofsky1, Bruno Boietti2, Delfina Cirelli2
1Hospital Municipal de Agudos Dr. Leonidas Lucero, Bahía Blanca, Buenos Aires, Argentina.
Insights
COVID-19 vaccines did not alter the time to peak symptom severity. However, analysis of hospitalized patients revealed that vaccination significantly reduced the risk of mortality, especially with two doses.
Area of Science:
- Infectious Diseases
- Vaccinology
- Public Health
Background:
- COVID-19 vaccines are crucial for preventing severe SARS-CoV-2 infections.
- A small percentage of vaccinated individuals may still experience moderate to severe illness.
Purpose of the Study:
- To compare mortality rates and time to peak disease severity between vaccinated and unvaccinated hospitalized COVID-19 patients.
- To analyze the impact of one versus two vaccine doses on outcomes.
Main Methods:
- Retrospective observational study across 36 hospitals in Argentina (January 2021 - May 2022).
- Inclusion of adult COVID-19 patients admitted to general wards.
- Comparison of time from symptom onset to peak severity using Cox regression with Propensity Score Matching (PSM).
Main Results:
- No significant difference in time from symptom onset to peak severity between vaccinated and unvaccinated groups (7 days IQR 4-12 vs. 7 days IQR 4-11).
- Propensity Score Matching (PSM) showed a reduced risk ratio (RR) for mortality in vaccinated patients (RR 0.73; 95% CI 0.60-0.88).
- Two vaccine doses demonstrated a further reduced RR for mortality (RR 0.6; 95% CI 0.46-0.79) compared to one dose (RR 0.7; 95% CI 0.45-1.03).
Conclusions:
- Vaccination against COVID-19 did not alter the disease progression timeline to peak severity.
- Hospitalized vaccinated patients exhibited a significantly lower risk of mortality compared to unvaccinated individuals.
- Two-dose vaccination regimens offered enhanced protection against mortality in hospitalized COVID-19 patients.
Introduction:
The COVID-19 vaccine became an effective instrument to prevent severe SARS-CoV-2 infections. However, 5% of vaccinated patients will have moderate or severe disease.
Objective:
to compare mortality and days between the symptom onset to the peak disease severity, in vaccinated vs. unvaccinated COVID-19 hospitalized patients.
Methods:
Retrospective observational study in 36 hospitals in Argentina. COVID-19 adults admitted to general wards between January 1, 2021, and May 31, 2022 were included. Days between symptoms onset to peak of severity were compared between vaccinated vs. unvaccinated patients with Cox regression, adjusted by Propensity Score Matching (PSM). Results in patients with one and two doses were also compared.
Results:
A total of 3663 patients were included (3001 [81.9%] unvaccinated and 662 [18%] vaccinated). Time from symptom onset to peak severity was 7 days (IQR 4-12) vs. 7 days (IQR 4-11) in unvaccinated and vaccinated. In crude Cox regression analysis and matched population, no significant differences were observed. Regarding mortality, a Risk Ratio (RR) of 1.51 (IC95% 1.29-1.77) was observed in vaccinated patients, but in the PSM cohort, the RR was 0.73 (IC95% 0.60-0.88). RR in patients with one COVID-19 vaccine dose in PSM adjusted population was 0.7 (IC95% 0.45-1.03), and with two doses 0.6 (IC95% 0.46-0.79).
Discussion:
The time elapsed between the onset of COVID-19 symptoms to the highest severity was similar in vaccinated and unvaccinated patients. However, hospitalized vaccinated patients had a lower risk of mortality than unvaccinated patients.
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