The fact that Pfizer wants to offer a third dose of the vaccine does not necessarily mean that people will look forward to it. Health authorities in the United States and internationally say that for now, those who are fully vaccinated appear to be well protected.
Globally, experts are closely monitoring to determine if people will need another dose. At the same time, many suggest that vaccinations should be a priority at the moment, noting that some troubling coronavirus mutations would not have occurred so quickly if much of the United States as well as the rest of the world would have met the first round of vaccination.
“If you do not want to see a new variant every week,” said Jennifer Nuzzo, a public health specialist at Johns Hopkins University, “we need to do more work to make sure all countries have more access to vaccines.” ”.
Here are some questions and answers about immunity and additional doses of vaccine.
WHAT IS PROMOTING THE DEBATE ON THE ADDITIONAL VACCINE DOSAGE?
U.S. health officials have long said that people may one day need a booster dose, as is the practice for many other vaccines. Studies are therefore being conducted to test different approaches: simple third doses, mixed dose tests with another brand of vaccine for a third dose, or a modified experimental booster dose to better respond different variants.
But last week, Pfizer and its German partner BioNTech announced that in August they plan to seek authorization from the Food and Drug Administration for a third dose, as it could increase levels of antibodies that fight the virus, possibly helping to avoid some disturbing mutations.
The companies have not released the data and U.S. health officials said booster doses are not yet needed and that the government, not vaccine manufacturers, will decide if and when that will change.
The World Health Organization said Monday that there is not enough evidence to show that third doses are needed. She said low doses should be shared with poor countries, and not used by rich countries as booster doses.
WHAT IS EVIDENCE THAT VACCINE PROTECTION CONTINUES TO BE STRONG?
An analysis last month by the Associated Press news agency found that almost all deaths from COVID-19 in the United States are occurring in the ranks of the unvaccinated.
In recent weeks, infections and hospitalizations have begun to increase as the highly contagious Delta variant spreads. But the Centers for Disease Control and Prevention says increases are being driven by less vaccinated parts, in a country that has enough doses if people would like to take them.
No vaccine is perfect. So fully vaccinated people will occasionally become infected, but these so-called penetrating cases are usually mild. Officials monitoring the need for booster doses are closely monitoring any major increases in serious infections that penetrate the protection offered by vaccines.
So far the news is good: People who were first in line for vaccines in December and January do not appear to be at higher risk of becoming infected than those recently vaccinated, Dr. said on Tuesday. CDC Jay Butler.
IS THE DEBATE ABOUT SUPPLEMENTARY DOSES ONLY WITH NEW VARIANTS?
No, scientists are also observing to see how weakened the overall immunity of people vaccinated against coronavirus is. This aspect may also require a booster dose.
Antibodies that fight viruses gradually fade. This is normal as the body does not need to be on high alert forever.
But antibodies are not his only defense. The moment those levels fall, the body has formed a state of reserve. Among them are memory B cells which, when exposed to the virus again, “explode and begin to divide like crazy” to produce new antibodies, said University of Pennsylvania immunologist Scott Hensley.
Another caveat: T cells that kill virus-infected cells to prevent the situation from getting worse.
Laboratory studies suggest that antibodies are not as potent against the Delta variant as they are against some previous versions of the coronavirus, but still serve to protect themselves. Specialists are more concerned about the prospect of future mutations that could escape today’s vaccines, something that can only be prevented by fighting viral spread wherever it occurs.
HOW ARE THE OTHER COUNTRIES COMING WITH THE DELTA VARIANT?
Real-life data in England, Scotland, Canada and Israel show that the most widely used vaccines in Western countries continue to provide strong protection. Researchers in Britain have found that two doses of the Pfizer vaccine, for example, are 96% protective against delta-type hospitalization and 88% effective against symptomatic infection.
Israel recently reported preliminary data suggesting that protection against mild Delta variant infection has dropped below, to 64%. But protection against serious illness remained high.
There is less information on how other vaccines work against the delta variant. Thailand announced this week that health workers who had received two doses of a Chinese vaccine will be given a booster dose produced by the AstraZeneca company.
CAN SOME PEOPLE NEED A DOSE OF STRENGTHENING IN FRONT OF THE NEXT PART OF THE POPULATION?
This is possible. Israel has just begun distributing third doses of the Pfizer vaccine to transplant recipients and other patients with weakened immune systems. Reason? People taking certain immunosuppressive drugs do not react as healthy people to vaccines, not just COVID-19 vaccines.
France already has a similar policy for the third dose for people with weakened immunity. Although not authorized in the United States, some people who have had a transplant require a third dose in hopes of more protection.
It has not yet been proven whether a third dose helps and, if so, who needs one and when. The first major strategy study on this issue is starting in thousands of patients in Norway.