Pfizer, Moderna's coronavirus vaccines effective even after first dose: Study
The coronavirus vaccines developed by American pharma giant Pfizer, with Germany's BioNTech, and the one manufactured by Moderna, another United States company, reduce the risk of infection even after the first dose, a study has found, reports Reuters. A study by the US Centers for Disease Control and Prevention (CDC) found that the vaccines worked two weeks or more after the first shot.
Nearly 4,000 people were evaluated for this study and the real-world data painted a pleasant picture. After the first shot of the two-dose vaccines, the risk of infection reduced by 80%. It fell by 90% two weeks after the course was completed. "This study shows that our national vaccination efforts are working," CDC Director Rochelle Walensky's statement read.
The participants were observed between mid-December and mid-March, regardless of their symptoms. The CDC monitored their health via medical reports. They were asked to get tested on a weekly basis. More than 62% of the volunteers had completed the two-dose course while more than 12% had received just the first dose of either Pfizer's vaccine or the one developed by Moderna.
Out of 2,961 vaccinated people (they had received at least one dose) and the 989 unvaccinated volunteers, 205 people tested coronavirus positive after RT-PCR tests. Of the positive people, 161 had not been administered the vaccine; eight were partially protected, and three contracted the infection after getting both the doses. Two people had to be hospitalized and no one died.
Though these findings are in line with the results of clinical trials, such experiments are important to show the efficacy of vaccines in the real world. "These findings also underscore the importance of getting both of the recommended doses of the vaccine in order to get the greatest level of protection against COVID-19, especially as our concerns about variants escalate," Walensky said, reports CNN.