The US Food and Drug Administration on Tuesday authorized the fourth booster COVID dose from manufacturers such as Pfizer/BioNTech and Moderna – to be administered to elder Americans starting from the age of 50 and older while young people (with compromised immune systems) from the age of 12 can take Pfizer/BioNTech booster shots and people from the age of 18 can take Moderna booster shots.

“Emerging evidence suggests that a second booster dose of an mRNA COVID-19 vaccine improves protection against severe COVID-19 and is not associated with new safety concerns,” the agency said in a release.

The new development came just weeks after both big pharma petitioned the FDA to authorize an additional booster shot of their mRNA vaccines. Pfizer on one hand requested that the booster shot be administered to adults from the age of 65 and above while Moderna sought approval for all adults.

FDA, however, took the decision to proceed with the booster shots even without convening its vaccine advisory committee according to a CNBC report.

Are you eligible for a fourth booster shot?

Currently, the primary group of people that are eligible to take the booster shot are elders from the age of 50 and above while certain children from the age of 12 who have compromised immune systems are also eligible (12 years and above for Pfizer/BioNTech booster shot and 18 and above for Moderna).

An exclusive list of young people with serious immune compromise includes those undergoing chemotherapy, organ and stem-cell transplant recipients, those with HIV, and so forth.

Even if one falls within either of the aforementioned groups, the vaccine can be administered at least four months after a first booster is administered.

How soon will the US start rolling out the booster shots?

Scientists and researchers have deduced that the long-term effectiveness of the COVID-19 vaccines decreases as time gets by which is why there has been recommendation of a second booster shots for the general public.

“The potential future requirement for an additional boost — a fourth shot for mRNA, or a third shot for Johnson & Johnson — is being very carefully monitored in real-time,” White House Chief Medical Adviser Dr. Anthony Fauci said in a February press briefing.

Some countries across the globe including Germany, Israel, the UK, and Chile have all approved a fourth COVID shot for older people or those with compromised immune systems and underlying health issues.

That said, the FDA will likely authorize the dose of mRNA vaccine to the general public in late fall or early winter according to a report made by The Wall Street Journal.

Who needs the fourth booster shot?

With lots of jabs currently in circulation, hospitalizations and deaths from COVID-19 is currently reducing. As of now, there are over 12 million new cases this past week according to the World Health Organization, there was a 23% decline in mortality. 

Still, that’s 33,000 deaths in one week which is still quite a lot.

“It is necessary for a fourth booster,” Pfizer CEO Albert Bourla told CBS’ Face the Nation earlier this month. The current three-shot protocol is “actually quite good against hospitalizations and deaths,” he added, “but it doesn’t last very long.”

Also, the FDA took its decision based on a large-scale study from Israel which showed the protection offered by a booster shot on those with underlying illnesses.

In the study which included half a million people, it was reported that a second booster shot has the potential of reducing death from COVID illness by a whopping 78% in adults from the age of 60 and above.

Just like there is need for a seasonal shot of flu vaccines, the same applies to COVID, according to a Bourla during a CVS Health Corporation event back in April, 2021.

“The COVID-19 virus looks more like the influenza virus than the poliovirus,” he added.

But Moderna said it requested approval for all adults 18 and up really “to provide flexibility” to the CDC and health care providers in deciding who needs another booster.

The company’s president, Stephen Hoge, told Business Insider last week he thought a fourth dose was probably necessary only for seniors and immunocompromised people. Others could make their own choice. 

“Is it necessary? I think that’s a strong word,” Hoge said. “I think it will provide a benefit to anyone who gets it.”

How long do COVID-19 vaccines remain effective?

According to researches, mRNA COVID-19 vaccines such as the ones offered by big pharma like Pfizer and Moderna offer great protection against complications from COVID-19 and booster shots are also meant to enhance the effectiveness of previous shots.

However, the potency of these vaccines reduces as time gets by.

In fact, there was a CDC report back in February that stated that hospitalization from mRNA vaccines dropped noticeably after just four months even with a booster shot.

The efficacy against the delta variant saw a 96% drop in hospitalization within two months of a third mRNA shot while the numbers dropped to 76% within four months.

During the omicron wave, protection from hospitalization fell from 91% within two months of an mRNA booster to 78% within four months. 

That said, a February study showed that the protection offered by mRNA vaccines decreases over time from 20% to 30% in six months after a third shot.

For symptomatic COVID-19 disease, vaccine effectiveness decreased by roughly 25% across the board at the six-month mark, and by 32% in people age 50 and older.

Another CDC study also showed that vaccines’ protection against hospitalization when omicron variant was dominant dropped from a high 91% within two months of a booster to 78% after just four months.