Dr. Fauci warns Americans may face having booster shots INDEFINITELY and says fully-vaccinated 'breakthrough' infections could still cause long COVID: FDA approves third dose for those with weakened immune systems

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Dr. Anthony Fauci said on Thursday that he can't rule out people having to have COVID-19 booster shots indefinitely as the virus continues to surge. 

Fauci, the chief medical advisor to the president, made his comments in an interview with Anderson Cooper on CNN in which he also warned that fully vaccinated people with so-called breakthrough infections can still get long-term COVID.

'We know a lot more than we did to start, but there's obviously, you know, we need to be humble in the face of this virus,' Fauci said.

Fauci said 'there are a lot of factors' that go into making decisions such as whether people will routinely have to get vaccinated against COVID-19 like an annual flu shot. 

He said researchers have already started conducting studies giving boosters to people who have already been full vaccinated, which have shown hopeful promise that future booster shots beyond a third jab may not be needed. 

'The good news about that is that the acceleration of the response goes way up. I mean even better than what you get with the two doses together. In other words, it goes up and up and then if you give a boost, it goes way up,' he said.

'I don't know for certain, but that could mean that you induce a response that's high enough - and durable enough - that you may not have to worry about what people are concerned about, needing a so-called boost every year or so.'

He continued: 'I would hope that the degree of elevation of response that we will see with the boost might actually give us a lot of wiggle room of not necessarily needing a boost often.'

'But I have to be, as you say, we are humble and we are modest about it. We don't know the answer to that.' 

Dr. Anthony Fauci said on Thursday that he can't rule out indefinite COVID-19 booster shots but that he hopes that, if booster shots are needed, just one will suffice

Fauci said 'the only way' the public health officials will become certain whether continued booster shots will be needed will be by conducting clinical and observational studies.

Cooper asked Fauci how future booster shots would be administered - namely if people would get them at their doctor's office and pharmacies or at mass vaccination locations.

'We don't want to get ahead of ourselves,' Fauci said. 

'Let's assume that this occurs that we're making a decision to do this, it would have to be in an orderly fashion. So you would not want to say, okay, now everybody's going to go getting a third boost. It will be an orderly fashion in a timely way.'

The U.S. Food and Drug Administration is working with vaccine makers Pfizer and Moderna to let some vulnerable people receive a third booster shot of their COVID-19 vaccines to improve their immune response. 

Rochelle Walensky, director of the Centers for Disease Control and Prevention, said on Thursday that the shots would be available to certain people who are moderately and severely immunocompromised.

That group, which she estimates sits at less than 3% of U.S. adults, would include people who have had organ transplants and some cancer patients.

Walensky said the CDC's Advisory Committee on Immunization Practices will meet on Friday to discuss this issue and offer recommendations.

Some Americans have already taken it upon themselves to get booster shots themselves, even before they're approved.

Fauci did not condemn those who had done so, but said he'd urge anyone considering it to wait until more data becomes available.  

In his interview on Thursday, Fauci also issued a stark long COVID warning for people with breakthrough infections - those that happen even when someone is fully-vaccinated.

He told Cooper that breakthrough infection sufferers are still at risk of long COVID, a term for those who suffer from lingering symptoms for months after their body clears the infection.

'Certainly if you get vaccinated and you get a breakthrough infection, you can get long COVID,' Fauci said.

'We don't have enough data in that to say if it's the same kind of risk of getting long COVID of others. But it is likely it would be less because you got a good deal of protection from your vaccine.'

A map shows the total number of coronavirus cases and deaths in the United States

A chart shows the daily number of new coronavirus infections per day since the start of the pandemic

A chart shows the daily number of new coronavirus infections per day in July and August

A chart shows the daily number of new coronavirus deaths per day since the start of the pandemic

A chart shows the daily number of new coronavirus deaths per day in July and August

A map shows the percentages of U.S. states that have been vaccinated so far

A chart shows the daily number of COVID-19 vaccinated in the United States

Fauci also warned that children can get long COVID - but the incidence of it is significantly lower than an adult. 

'It's just a few percent of children, whereas with the adult it's anywhere from 10% to up to 30%,' he said.  

Mayo Clinic researchers has conducted an alarming study, which was published on a pre-print server medRxiv.org - meaning it has not yet been peer-reviewed.

The study found that the Pfizer-BioNTech vaccine was only 42% effective against infection in July while the Moderna vaccine was only 76% effective.

It has been noted that the drop in efficacy happened around the time the Delta variant of the coronavirus started sweeping the globe - raising concerns that booster shots will be needed to particularly protect against it and other future variants.

Earlier this month, Pfizer and Johnson & Johnson expressed that they were still confident that their vaccines can protect against COVID-19 variants despite a recent report warning about hundreds of breakthrough infections in a Massachusetts town. 

A healthcare worker fills out a Covid-19 vaccination card at a community healthcare event in a predominately Latino neighborhood in Los Angeles, California on Wednesday

The vaccine cards allot room for future doses of the COVID-19 vaccine

A woman walks past a sign of COVID-19 vaccination at a pharmacy in New York on Wednesday

A healthcare worker prepares a dose of the Pfizer-BioNTech vaccine at West Philadelphia High School in Philadelphia last Tuesday

The recent CDC study focused on an outbreak in the Cape Cod town of Provincetown, a heavy tourist hotspot in Barnstable County, after the July 4 weekend.

It found 469 cases of COVID-19 associated with multiple summer events and large public gatherings - even though 69% of Massachusetts residents were vaccinated.

Researchers said that 346 cases - or 74% - occurred in fully vaccinated people. Scientists did DNA sequencing on 133 of those patients and found that 119 of them, or 89%, had the Delta variant.

The study found that 79% of vaccinated patients with breakthrough infection were symptomatic. There were five COVID-19 patients who were hospitalized, four of whom were fully vaccinated - though no deaths were reported.

Researchers found that the Delta variant is 'highly transmissible' but that 'vaccination is the most important strategy to prevent severe illness and death.'

The study found that viral loads, which indicate the likelihood that someone could transmit the virus to others, were similar among 127 fully vaccinated people and 84 people who were unvaccinated or partially vaccinated.

The new study came after the CDC recommended that even those who are fully vaccinated should wear masks in indoor public settings in areas where COVID-19 transmission is high or substantial.