Impact of vaccination on morbidity and mortality in adults hospitalized with COVID-19 during the omicron wave in the Jazan Region, Saudi Arabia.

OBJECTIVES: To evaluate the impact of coronavirus disease-19 (COVID-19) vaccination on morbidity and mortality in adults hospitalized with COVID-19 during the omicron wave in the Jazan Region, Saudi Arabia. METHODS: A 6-month record-based historical prospective study enrolled COVID-19 adult patients admitted between January and June 2022. Individuals were classified into 3 groups according to their immunity status (immunized, partially immunized, and not immunized). Death, intensive care unit (ICU) admission, and mechanical ventilation were identified as the primary outcomes, collectively referred to as "serious outcomes". On the other hand, the length of hospital stays longer than 5 days was categorized as a secondary outcome. Multiple logistic regression analysis was used to evaluate independent factors and the relationship between the outcomes and vaccination status. RESULTS: Among the 634 COVID-19 patients admitted to Jazan hospitals, 46.4% were fully immunized, 19.7% were partially immunized, and 33.9% were not immunized. Not being immunized was significantly associated with ICU admission (odds ratio [OR]=1.91, 95% confidence interval [CI]: [1.17-3.11]; p=0.009), mechanical ventilation (OR=2.11, 95% CI: [1.25-3.56]; p=0.005), increased length of hospital stays (OR=1.79, 95% CI: [1.24-2.59]; p=0.002), and death (OR=3.03, 95% CI: [1.85-4.98]; p<0.001). CONCLUSION: Our study underscores the importance of a comprehensive approach for managing COVID-19 patients that includes vaccination against the disease.

Real-world effectiveness of COVID-19 vaccines: A retrospective cohort study of vaccinated individuals in Jazan, Saudi Arabia.

BACKGROUND: COVID-19 (Coronavirus Disease 2019) vaccinations are a critical control measure for the coronavirus pandemic that began in 2019. Several COVID-19 vaccines have been developed, and their effectiveness will almost certainly vary. OBJECTIVE: This study aimed to assess how effective two doses of the Pfizer and Oxford-AstraZeneca vaccines were in preventing SARS-CoV-2 infection six months after administration. METHODS: This is a retrospective cohort study of adult individuals from the Jazan Region of Saudi Arabia who received their second dose of the COVID-19 vaccine [Pfizer and Oxford-AstraZeneca (ASZ)] between April and June 2021. The monitoring and follow-up period continued until the end of January 2022. Data were retrieved from the Health Electronic Surveillance Network and National Vaccination Records. Logistic regression was performed to assess the risk of COVID-19 infection among the vaccinated subjects. RESULTS: This study included randomly enrolled 4458 participants in Jazan who received two doses of the COVID-19 vaccine during the research period. The majority of them received the Pfizer vaccine (3136/4458; 70.3%), while the remaining received the ASZ vaccine (1322/4458; 29.7%). The study participants' mean age was 59.7 years, with a male-to-female ratio of 1.9:1.0 (2920:1538). The results showed that the Pfizer and ASZ vaccines' protection against infection decreased from 93.2% and 90.2%, respectively, during the first three months, to 68.5% and 68.1% after a six-month interval. In the current study population, being Saudi Arabian, younger as well as having longer intervals between vaccines or crossing a 6-month period after the second vaccine dose were factors linked to higher rates of breakthrough infections. CONCLUSION: Our findings revealed variations in the efficacy of different COVID-19 vaccine types against COVID-19 breakthrough infections. The Pfizer (mRNA-based) vaccine was found to be relatively more effective than the ASZ (DNA-based) vaccine.