news agency

Natural immunity protected more than vaccines during delta wave in the US, according to study

During the last wave of coronavirus in U.S driven by the delta variant, unvaccinated people who survived COVID-19 were better protected than those who were vaccinated and not infected before, according to a new study.

The finding adds to the debate about the relative strengths of natural immunity compared to that acquired through the SARS-CoV-2 vaccine, and has the approval of the federal agency of the Centers for Disease Control and Prevention (CDC) of the United States.

However, the paper’s authors cautioned against relying on infection as a strategy to acquire immunity given the higher risk of hospitalization, long-term impacts, and death in unvaccinated people, compared to those who do get vaccinated.

“The level of protection offered by vaccination and survival from a previous infection changed during the study period. Vaccination remains the safest strategy to protect against COVID-19,” the CDC said in a statement.

The analysis was done before booster injections became widely available and also before the appearance of the omicron variant, for which both immunity from the vaccine and from previous infection appeared to decrease.

The new study involved patients in New York and California between May 30 and November 30, 2021.

For the week of Oct. 3, case rates among vaccinated people without prior COVID-19 were about six times lower in California and five times lower in New York, compared to unvaccinated individuals without prior COVID-19 .

But infection rates were substantially lower among people with prior COVID-19 — up to 29 times in California and 15 times in New York — among unvaccinated people with a prior diagnosis, compared with those who were unvaccinated and unvaccinated. had COVID-19.

Before delta became dominant, vaccination conferred greater immunity than infection itself. But the relationship changed when the variant became predominant in late June and July.

The highest protection in the study was among those with vaccines and prior COVID-19, and hospitalization rates followed a similar pattern.

However, the study could be affected by an effect known as “selection bias”, since it excluded people who died and the vast majority were not vaccinated.

Other research, including a notable scientific paper from Israel in August, also found that natural immunity was more potent than vaccines during the delta surge.

But the US CDC had previously taken the opposite position, based on pre-delta data.

“Further studies are needed to establish the duration of protection against prior infection by variant type, severity, and symptomatology, including the omicron variant,” the article concluded.

.

You may also like

Hot News

TRENDING NEWS

Subscribe

follow us