"I would not at all be surprised that the adequate, full regimen for vaccination will likely be three doses," he said during a briefing of the White House coronavirus response team. However, he did say that regulators will have to make that determination.
Fauci presented Israeli data showing the waning immunity to the virus after about eight months. This, he said, supported the rationale for the necessity of getting booster shots.
After more delta variant cases surged in Israel in early summer, the number of positive cases and severe COVID-related illnesses rose among vaccinated individuals. By then, many Israelis had been vaccinated for more than half a year.
The unexpected delta surge forced Israel to begin administering booster shots using the Pfizer vaccine beginning July 30 to older individuals who are most likely to become ill of the disease. Less than two weeks later, Israel saw a positive impact that Fauci said has a "greater-than-tenfold diminution in the relative risk of both confirmed infection and severe disease."
Fauci also said that the protection provided by a third shot was dramatic and durable, considering that the risk of infection dropped by as much as 84 percent three weeks after a third shot, compared to the two-shot regimen.
Initially, two doses of mRNA technology vaccine (manufactured by Pfizer and Moderna) were considered sufficient, but virologists now believe immunity needs to be enhanced, thus recommending the third shot. Health experts also say that it is not uncommon for vaccines to require more than two doses: for instance, vaccinations for hepatitis B as well as HPV require third doses, with the third dose administered several months after the second.
The administration called to begin dispensing booster shots on September 20. Vulnerable individuals such as seniors in long-term care, immunocompromised individuals and health care workers are prioritized, while the rest of the population are advised to receive their third shot eight months after receiving their second. (Related: Scientists increasingly question the necessity of booster shots; no data show they will help at all.)
There are still many Americans who have not been vaccinated at all: as of September 1, only about 53 percent have been vaccinated. This number is not high enough to stop the spread of the coronavirus to build herd immunity.
Expert review of scientific evidence has also concluded that the COVID-19 booster shot is not needed at this time for the general public. They indicated that there are risks to distributing boosters too soon, such as myocarditis, which is an adverse effect that is more common after the second dose of mRNA vaccines.
"If unnecessary boosting causes significant adverse reactions, there could be implications for vaccine acceptance that go beyond COVID-19 vaccines," the health officials wrote.
They also argued that a more targeted vaccine against specific variants of the COVID-19 virus may be more effective than another dose of the existing vaccine.
The Biden administration may, however, face hurdles as it prepares to roll out the third dose of vaccines. Some sources are saying that booster shots could only be available for those who received the Pfizer-BioNTech vaccine.
This is in contrast with the president's initial plan of administering booster shots for those who had either Pfizer or Moderna mRNA vaccinations.
Because of this, sources said that regulators want more data regarding booster vaccinations to safely recommend them to the broader population.
About 75 percent of Americans are said to be enthusiastic about booster vaccinations, however, the World Health Organization and others have pushed back on the rollout due to other countries struggling with vaccine inequity. They have called on countries to share their vaccine doses with the developing world instead of using them as booster doses for their own populations.
Fauci said, "I would hope that the countries that are boosting their populations similar to what we understand are the importance of the global necessity to essentially suppress this at the global level."
He also said that the United States already donated 130 million doses to 90 countries -- a contribution that far exceeded that of any other developed nation.
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