The Effect of Vaccination with Pfizer-BioNTech or CoronaVac on Disease Prognosis Among Hospitalized COVID-19 Patients.

OBJECTIVE

The Turkish Ministry of Health offered two types of vaccines by January 13, 2021, which are CoronaVac (Sinovac Biotech, China) and Pfizer-BioNTech. We aimed to describe the impact of the CoronaVac and Pfizer-BioNTech vaccines on clinical outcomes among hospitalized patients during a six-month period.

METHODS

We included patients older than 18 years old and hospitalized because of COVID-19 when the vaccines were available. We conducted the study at Koç University Hospital and American Hospital between June 2021, six months after the vaccination started, and December 2021.

RESULTS

In total, 444 RT-PCR confirmed hospitalized patients were included. The mean age of the patients was 59 (standard deviation [SD]=18), and 42.8% were female. The most common comorbidity was hypertension (39%), followed by diabetes mellitus (27%), cardiovascular diseases (18.4%), chronic lung diseases (14.6%), cancer (9.2%), and chronic renal diseases (8%). In multivariate analysis, no vaccination (OR=4.7, CI=2.25-10.06; <0.001), age >65 (OR=5.2, CI=2.25-11.98; <0.001), cancer (OR=7.6, CI=3.04-19.31; <0.001), and chronic kidney disease (OR=3.1, CI=1.14-8.74; =0.026) significantly increased mortality in COVID-19 patients. Eighteen percent of patients were in the intensive care unit (ICU). One hundred eighty-one patients (40.8%) were non-vaccinated before their admission, and their mortality (17.6%) was higher compared to the patients who were vaccinated with at least one type of vaccine (=0.002). None of the patients who received two doses of Pfizer-BioNTech vaccines died.

CONCLUSION

Among the inpatients with COVID-19, the predictors for mortality were being unvaccinated, older age, cancer, chronic kidney disease, and cardiovascular diseases. Among the vaccinated inpatients, having two doses of the Pfizer-BioNTech vaccine was the only effective protective measure against mortality, and two doses of the CoronaVac vaccine had no significant effect in preventing fatality.