Natural immunity to Covid infection could be stronger than vaccination to protect against the Delta variant: Recovered patients are 13 times less likely to become infected than those with Pfizer breasts, according to an Israeli study
- A new Israeli study examined thousands of people who had been vaccinated against COVID-19 or who had not been vaccinated but had previously been infected.
- Participants with double punctures were 5.96 times more likely to be infected and 7.13 times more likely to experience symptoms.
- After three months, the risk of infection was 13.06 times higher among immunized individuals and they were 27 times more likely to experience symptoms.
- Researchers say the study has many limitations, including the dominant Indian variant “Delta” and that no participant testing is required.
- The study does not discourage vaccination because unvaccinated people are more likely to be infected with Covid or hospitalized than vaccinated people.
A new study suggests that natural immunity to previous COVID-19 infection may offer stronger protection against the Indian variant of the Delta than immunity to full vaccination.
The researchers compared people who had received two doses of the Pfizer-BioNTech COVID-19 vaccine with unvaccinated individuals who had recovered from the virus.
They found that participants with natural immunity were up to 13 times less likely to contract Covid than those who received it twice.
The Maccabi Healthcare and Tel Aviv University team notes that their study, which has not yet been peer-reviewed, has many limitations, including the more highly transmissible Delta variant that is dominant at the time and does not require participants take tests.
The study looks at advanced infections and does not discourage vaccination with a recent report from the Centers for Disease Control and Prevention (CDC) that found that unvaccinated people still have five times more COVID-19 infections and 29 times more. hospitalizations that people who have had had their shots.
A new study found that participants with double punctures were 5.96 times more likely to be infected and 7.13 times more likely to experience symptoms.
After three months, the risk of infection was 13.06 times higher among immunized individuals and they were 27 times more likely to experience symptoms.
For the study, published on the prepress server medRxiv.org, the team examined more than 800,000 people divided into three groups.
This included people who received both doses of the Pfizer vaccine and never had Covid, unvaccinated people who had been previously infected, and people who had the virus and have also received a single dose of the vaccine.
The study was conducted after the Delta variant became dominant in Israel, which has been shown to elude vaccines more easily than older strains.
The researchers found that people were completely vaccinated, but that they were much more likely to have an “advanced” covid infection than people with natural immunity to the disease.
Overall, participants with double punctures were 5.96 times more likely to be infected and 7.13 times more likely to experience symptoms such as cough, fever, and difficulty breathing.
They also examined the likelihood of vaccination after three months.
The researchers found, in this case, the 13.06 times higher probability of infections among immunized individuals and were 27 times more likely to experience symptoms.
People who had recovered from the virus and had been vaccinated were even less likely to have an advanced infection.
The team notes that there are several limitations. First, the study only examines the protection offered by Pfizer vaccines and does not address other approved vaccines or additional protection provided by a third dose.
Second, although the study controlled for factors such as age, sex, and region of residence, there may be differences in group behaviors (such as social distancing and mask use) that did not. were taken into account.
Dr Andrew Croxford, a UK immunologist, also points out that it is likely that someone who tested positive for COVID-19 will not try reinfection again.
“If you’ve been positive and isolated for weeks with a major break, how likely are you to try again instead of thinking ‘I’ve already had it, so I’m sure it’s something else’?” he tweeted.
“Are people who reject the vaccination or people with a previous infection less likely to get tested?”
However, if the findings are confirmed through a peer review, it could have implications
“This study showed that natural immunity confers more lasting and stronger protection against infections, symptomatic diseases, and hospitalization caused by the Delta variant of SARS-CoV-2,” the authors wrote.
“People who were previously infected with SARS-CoV-2 and received a single dose of the vaccine gained additional protection against the Delta variant.”
