- Two recent studies have found that infection-induced immunity can last for months.
- Experts believe that vaccination will make the immunity caused by infection even longer.
- The researchers found that many people who recovered from COVID-19 and later received an mRNA vaccine may not need additional booster images.
Whether we will develop immunity to COVID-19 or how long it will last if we do so is a mystery from the early months of the pandemic.
However, two new studies help us better understand how our immune system adapts to the infection and what it may mean for vaccination.
Studies published in May found that infection-induced immunity could last for months or more. But experts believe that vaccination may extend the duration of this immunity.
Another important finding from both studies was that many people who recovered from COVID-19 and later received an mRNA vaccine (such as Moderna or Pfizer-BioNTech) may not need booster images.
Both studies looked at people exposed to the coronavirus about a year earlier.
According to one
Another study, which has not yet been reviewed, found that these immune cells can mature and heal in about a year after infection.
“The data show that immunity in convalescent individuals will be very long-lasting and that convalescent individuals who receive available mRNA vaccines will produce antibodies and memory in B cells that must be protected against circulating variants of SARS-CoV-2,” the authors write. of the study.
According to Dr. Miriam Smith, chief of infectious diseases at Long Island Jewish Forest Hills, Northwell Health in New York, our immune system includes B-cells, which are a type of white blood cell (WBC) responsible for
“They originate and mature in the bone marrow, then migrate to the spleen and lymph nodes,” she told Healthline. “They are activated in cells in response to an antigen, virus or bacterium.”
Smith explained that B cells have receptors on their surface that can bind to these pathogens.
“With the help of T cells, another component of the immune system, B cells will differentiate into plasma cells to produce antibodies that will capture a virus or bacterial invader and allow other cells (macrophages) to destroy the invader,” Smith said. .
She said that after the infection, the “memory” B cells remained around, so if the same virus or bacterium invaded again, the immune system “remembered” and reactivated to fight it.
“It’s still important to get these people vaccinated,” said Dr. Len Horowitz, a lung specialist at Lenox Hill Hospital in New York. “As far as we know, their immunity may not last longer than the 11 months that have been documented.”
He explained that this means that people who have had the disease cannot rely on a previous infection to achieve immunity in the way that people could with measles, mumps and rubella, “and this is not necessarily a permanent immunity. but let’s say for life, “he added.
According to Horowitz, reinfections do not necessarily mean a milder case of the disease.
“It can be softer, it can be the same severity and it can be worse,” he explained. So there are a lot of things we don’t know.
“We do not know the exact percentage [of reinfection]Horowitz said. “We know it can happen, we know it’s not common, but it’s not uncommon.”
If reinfection is possible, Horvitz said, “then you can spread it to other people.”
He said this meant that people who became infected with another infection would not contribute to herd immunity.
“So it’s important that if you had COVID, you don’t rely on the fact that you had it and you probably won’t get it again,” Horwitz said. “And you have to be immunized, because the antibodies you get from an infection are different from the antibodies you get from the immunization. They are two different measurable antibodies. “
These new studies also suggest that the majority of people who recover from COVID-19 and are later immunized with one of the mRNA vaccines will not need booster shots to maintain protection against the virus.
However, vaccinated people who have not had a previous infection are likely to need booster photos, as well as the small number of people who have had the disease but have not given a strong enough immune response.
According to Horowitz, booster photos can help.
In fact, there was an article this week in the New York Times where they looked at the response of people who had COVID and been vaccinated and had an amazing immune response – much more than someone who was not COVID naive. [hadn’t had a previous infection],” he said.
“So, someone who has had COVID-19 is immunized, then there should never be a booster,” he continued. “They have more immunity than someone who has been vaccinated [and never had a previous infection], it seems. “
Two recently published studies found that people recovering from COVID-19 developed antibodies that could last for almost a year.
Experts say that reinfection, although unusual, can still occur – and vaccination with one of the mRNA vaccines (such as the Moderna of Pfizer-BioNTech vaccine) can significantly boost immunity.
Experts also say that people who have had COVID-19 may not need booster shots to maintain protection, as mRNA vaccines elicit such a powerful immune response in this group.
However, experts warn that people who have not had a previous infection are likely to need them.