According to a large-scale Israeli study, people who had recovered from the coronavirus and had been vaccinated with even a single dose of the Pfizer-BioNTech vaccine were much better protected against re-infection than people who have natural immunity. The study was published in the Annals of Internal Medicine this week and revealed that people who had gotten vaccinated after getting infected with COVID-19 were 82% less likely to get re-infected after the first bout. The study further revealed that those who had gotten a shot after recovery were also 76% less likely to have asymptomatic re-infection, as opposed to those who are unvaccinated.
This research obtained samples from almost 108,000 Israelis, who were 16 or above, and had been infected before they got vaccinated. This made it the largest study of its kind to have been conducted. The data had been taken just before the Omicron wave hit, when it had been relatively rare for people to get re-infected. Even though they do give a picture of the infection patterns, the authors of the Israeli study said that conclusions could not be drawn on serious illnesses because the hospitalization rates had been very low. The focus of the study were people who had caught the coronavirus before getting inoculated.
Maccabi Health Services’ research arm conducted the peer-reviewed study. Since the data for the study had been obtained before the fifth wave of the coronavirus began in Israel, it does not provide any insight into the immunity of people who have recovered from this particular variant. A number of Omicron patients have gotten two to three doses, which makes it possible that they could have a significantly higher level of protection, as opposed to their unvaccinated counterparts. However, no predictions were made by the study about this aspect.
While the study does not cover the latest wave, the researchers said that it makes a strong argument for the fact that the ‘hybrid’ immunity amongst those who are vaccinated offers much better protection against the coronavirus than just natural immunity. The team was led by Dr. Tal Palaton and Dr. Sivan Gazit. They said that not only was the risk of re-infection reduced significantly in patients with even a single vaccine dose after infection, but he risk for the symptomatic disease was also reduced. The research was lauded by the Israeli medical community as a significant one, particularly because newly recovered patients are greater in number than those who are unvaccinated.
There are many situations where people who have recovered from the virus believe that they do not require a vaccine. Tel Aviv University’s virus expert, Dr. Yariv Wine, said that the study was quite sensible. He was not part of the study, but said that the purpose of the vaccine is to ‘train’ the immune system to respond to a pathogen in a way that prevents active disease, which means it leads to immune development. He added that the new study showed how even a single dose can activate the immune system.