COVID-Infected People Who Were Vaccinated had the Best Protection During Delta, a Study by the CDC Found

According to a CDC research, those vaccinated who had previously contracted COVID had the best protection during the delta virus outbreak.

Researchers used New York and California data between May and November 2021 to investigate the influence of immunization and past COVID-19 infection on the case and hospitalization rates.

According to a report published Wednesday by the Centers for Disease Control and Prevention, both immunization and past infection gave protection against further infection and hospitalization due to COVID-19 during the current wave in the United States.

Trials Involved Four Possible Categories of People

The study focused on four core groups of people: those who were unvaccinated but had not previously been infected; those who were unvaccinated but had previously been infected; those who were vaccinated but had not previously been infected; and those who were vaccinated but had previously been infected.

The study discovered that, before June, when delta became the prevalent variation, vaccination provided stronger protection against emerging infections than the previous infection did against reinfection.

However, as delta became dominant, this pattern reversed, with the previous infection providing superior protection.
Nevertheless, this also overlaps with a period when many Americans were many months off from receiving their vaccinations and before boosters were approved.

Notably, the study was done before the development of the omicron variety and before the widespread availability of booster injections; consequently, researchers emphasized that the findings could not be immediately transferred to the country’s current spike.
Furthermore, the study excluded data on the degree of initial infections, and hospitalization data was only gathered from California.

Two doses of vaccination provided great protection against hospitalization during the delta wave, and researchers emphasized that being immunized remained a safer alternative than catching COVID-19.

Researchers State Getting a Vaccine Was Still a Better Option Than Getting COVID-19

The research discovered that vaccination protection fades with time, and the farther someone is from their last vaccine injection or a past illness, the more likely they would have a breakthrough infection.

When asked repeatedly during a press conference on Wednesday whether the data showed that when delta was prevalent, having an infection provided stronger protections against reinfection than being vaccinated, a CDC representative insisted that vaccination is still the best way to protect oneself.

According to the researchers, the data confirms that immunization remains the safest option for guarding against COVID-19.

The CDC also referenced recent research that shows that even when time passes after an infection, immunization still gives better protection against COVID-19 than previous infection alone, emphasizing the importance of staying up to speed on the COVID-19 vaccine.

While omicron has been spreading, the CDC stated it would publish new data on COVID-19 immunizations and boosters later this week.

Tonia Nissen
Based out of Detroit, Tonia Nissen has been writing for Optic Flux since 2017 and is presently our Managing Editor. An experienced freelance health writer, Tonia obtained an English BA from the University of Detroit, then spent over 7 years working in various markets as a television reporter, producer and news videographer. Tonia is particularly interested in scientific innovation, climate technology, and the marine environment.