Effectiveness of COVID-19 Vaccination in Reducing Severity Among SARS-CoV-2 Infected Patients: A Prospective Study...

Coronavirus disease 2019 (COVID-19) is a lethal global pandemic that originated in Wuhan, China at the end of 2019. As with other viral infectious diseases, the introduction of an effective vaccine is crucial for stopping the spread of the pandemic.In Iraq the COVID-19 vaccination campaign started on March 2, 2021.

To determine the influence of the vaccine on new virus infection in Baghdad in terms of its effectiveness on the illness, hospitalization, and mortality.

A prospective observational study of patients with SARS-CoV-2 infection who were had a newly positive Real time PCR testing for SARS-CoV-2 at Al-Yarmouk Hospital or Al-Adel Primary Health Care Center, and correlate their symptoms to their state of vaccination.

A total of 539 patients tested positive for COVID-19 via PCR (328 females and 211 males). Among these, 265 patients (49.2%) were vaccinated, while 274 (50.8%) were not. Being vaccinated and receiving the full doses showed the strongest association with decreased disease severity, reduced hospitalization rates, and lower mortality rates (p < 0.05 for all). The type of vaccination was significantly correlated with disease severity (p < 0.001), with more severe or critical symptoms reported in patients vaccinated with BBIBP-CorV compared to those vaccinated with BNT162b2 or ChAdOx1 nCoV-19 (AZD1222). However, no correlation was found with hospitalization or mortality rates.

COVID-19 vaccination, while not preventing infection, markedly reduced disease severity and mortality-especially with full dosing and among high-risk groups. The differential effectiveness observed among vaccine types highlights the importance of optimizing vaccine strategies based on real-world outcomes, particularly in resource-constrained settings like Iraq.