According to new research, COVID immunization provides long-term protection against the severe effects of the infection. The findings were published in the prestigious ‘New England Journal of Medicine’. The advent of delta and omicron variants has sparked debate about whether low immunity or more transmissible variants are responsible for successful infection. According to the findings, breakthrough infections are caused by a drop in immunity, but the vaccines provided protection against hospitalization and serious illness nine months after the first shot.
“The important message from our study is that unvaccinated individuals should be vaccinated immediately,” said Danyu Lin, PhD, Dennis Gillings, Distinguished Professor of Biostatistics at the UNC Gillings School of Global Public Health. “Our findings also highlight the importance of booster shots, especially for older individuals,” Lin said.
According to the study, two months after the first dose, the effectiveness of the Pfizer and Moderna mRNA vaccines in reducing the risk of COVID-19 peaked at about 95%, and then gradually decreased. At seven months, the efficiency of the Pfizer vaccine had dropped to 67%, while the effectiveness of Moderna Vaccine remained at 80%. From mid-June to mid-July, when delta variation was increasing, the efficiency of the two mRNA vaccines decreased significantly among early receivers. One month after injection, the Johnson & Johnson adenovirus vaccine was 75% effective, but five months later, it was just 60% effective.