It's a question that global scientists have been trying to answer since the start of the coronavirus pandemic: How much immunity does an individual have against COVID-19 after infection, and how does that immunity compare to protection levels alloted by available vaccines?
The U.S. Centers for Disease Control and Prevention (CDC) published its first study seeking to answer this question last week in its latest Morbidity and Mortality Weekly Report, with researchers concluding that unvaccinated people with recent COVID infection were five times more likely to be reinfected when compared to those who were fully vaccinated without prior infection.
CDC researchers concluded that vaccination from mRNA-based vaccines--developed by Pfizer
"We now have additional evidence that reaffirms the importance of COVID-19 vaccine, even if you have had prior infection," said CDC Director Dr. Rochelle Walensky said in a statement.
"This study adds more to the body of knowledge demonstrating the protection of vaccines against severe disease from COVID-19," she added. "The best way to stop COVID-19, including the emergence of variants, is with widespread COVID-19 vaccination and with disease prevention action such as mask wearing, washing hands often, physical distancing, and staying home when sick."
The study analyzed data from the VISION Network that showed among more than 201,000 adults hospitalized with symptoms similar to COVID-19, unvaccinated Americans with prior infection with 3 to 6 months were 5.49 times more likely to have laboratory confirmed COVID-19 infection than those who were fully vaccinated within the same time period with mRNA COVID vaccines.
The study was conducted at 187 hospitals across nine states between Jan. 1 to Sept. 2 of this year, when the highly contagious Delta variant became the dominant strain of the coronavirus in the United States.
CDC researchers added that additional studies are needed to evaluate the immunity provided by the Johnson & Johnson
