In the US, pharmaceutical companies Pfizer and BioNTech intend to ask the Food and Drug Administration (FDA) in August to urgently authorize the use of the third dose of their coronavirus vaccine.
The company claims that antibodies weaken over time, and the third dose should be a booster to protect against the aggressive Delta strain. Who else is talking about the third dose of the vaccine, what research exists on this topic?
Why is Pfizer working on a booster dose
The company said Thursday, July 8, that a third shot in 12 months could dramatically boost immunity. Antibodies weaken over time and therefore research is underway to determine if boosters are needed and when exactly they are needed.
Dr. Mikael Dolsten of Pfizer cited early research data: after the third dose of vaccine, the level of antibodies in humans jumps 5-10 times compared to the second dose months earlier, reports the Associated Press.
The doctors are concerned about a new aggressive strain Delta. The company cites an example of research that the Pfizer vaccine and others provide reliable protection against the Delta option.
Two doses of most vaccines are critical to producing high levels of antibodies to all strains of the coronavirus, not just the Delta variant. It's worth noting that some countries where the pandemic is raging are still trying to get vaccines.
Dolsten pointed to data from the UK and Israel showing that Pfizer is neutralizing the Delta strain. It is speculated that when antibody levels get low enough, the mutated virus could eventually cause mild infection before the immune system returns to normal.
FDA approval will be the first step. This will not mean that the Americans will be offered booster vaccinations. Dr.William Schaffner, a vaccine expert at Vanderbilt University Medical Center, says public health authorities will have to decide if they are really needed, especially since millions of people have not even received their first dose.
Hours after Pfizer's announcement, US health officials said fully vaccinated Americans did not need a booster dose yet. Experts from the FDA, CDC, and national health institutes are investigating whether a booster dose may be necessary.
"We are ready for booster doses if and when science shows they are needed," the FDA and CDC say.
In the US, 48% of the population is fully vaccinated so far, and in some parts of the country the immunization rate is much lower (where there is an increase in the Delta strain). The CDC director said highly immunized areas of America are returning to normal, while hospital admissions are on the rise elsewhere.
The blood of several dozen people who received 1 dose of Pfizer or AstraZeneca, "almost did not cope" with the Delta, reports Nature. A few weeks after receiving the 2nd dose, almost everyone had an immunity boost sufficient to neutralize Delta.
French scientists tested unvaccinated people who recovered from the coronavirus and found that their antibodies were four times less effective against the new strain. A single dose of the vaccine dramatically increased antibody levels, causing cross-protection against Delta.
Laboratory experiments add to the evidence that mutations do not "escape" vaccines widely used in the West. Scientists also emphasize the importance of vaccinating more people in the world before the virus mutates even more.
British researchers found that two doses of Pfizer vaccine were 96% effective against hospitalization with Delta and 88% effective against infection. This finding was supported by Canadian researchers last weekend, while an Israeli report said that protection against mild Delta infections may have dropped to 64%.
The World Health Organization (WHO) has said the most vulnerable will need booster vaccinations every year. WHO reviews annual boosters for high-risk individuals and vaccinations every two years for the rest of the population.
In England, in the fall, they can begin to vaccinate citizens with a third dose. First of all we are talking about category 50+ and people with chronic diseases.
At this stage, the following options are being studied: vaccination with modified drugs to combat mutated strains or inoculation with one of the vaccines that are already in use.
Scientists who are studying the use of a third unmodified dose believe it will give recipients a massive amount of antibodies strong enough to stop infection from new strains. Also an interesting fact: in the case of the third vaccination, the protection is stronger when using a different vaccine (2 doses of AstraZeneca + 1 Pfizer).
The Department of Health will purchase 60 million doses of Pfizer, many of which will be used for the third revaccination.
Early test results raised hopes that both approaches could nullify any threat posed by new and existing variants of the disease. One of the senior officials told the newspaper that soon the country's leadership will have something to tell about the revaccination program, and now everything looks optimistic.