Head of US FDA?s advisory group: ?We never expected Covid vaccines to be so good, so effective?

It is likely that in the "before times", few Americans knew that independent experts advised the US Food and Drug Administration (FDA) on the safety and efficacy of vaccines, and that the FDA usually took their advice.

Less than a year into the Covid-19 pandemic, that quickly changed.

The Vaccines and Related Biological Products Advisory Committee became arguably the most closely watched group of experts in America's federal government. The media followed hearings, and thousands of Americans tuned in live to see whether these scientists considered Covid vaccines safe and effective.

For the chair of that advisory group, Dr Arnold Monto, a professor at the University of Michigan's school of public health, the last year has been a revelation.

Ultimately, experts and Monto did say vaccines were safe and effective, and the FDA authorized Covid-19 vaccines for emergency use shortly thereafter. More than 237 million Americans have since received a vaccine. Through several more hearings, VRPAC has recommended vaccines to everyone older than five and booster doses to everyone older than 18.

Now, Monto is the author of a recent article in the New England Journal of Medicine, in which he considers the long-term future of the pandemic, and whether scientists can learn from another disease that was once pandemic - influenza.

In an interview with the Guardian, Monto considered both this possible future - in which Covid-19 "is not going away, in spite of how well our vaccines perform" - and an incredible and perplexing year of vaccine distribution.

"The first thing is [that] we never expected our vaccines to be so good, so effective," said Monto. "This was a very happy surprise to everybody - and it was a surprise."

He and other scientists watched as a vaccine against Covid-19 was developed faster and more effectively than any dared to hope. Then Monto watched in astonishment as tens of millions of Americans refused to take them.

Nevertheless, he added: "Those of us who are on the front lines here, in terms of development or evaluation, are so incredulous about people not wanting to get vaccinated."

Perhaps the most frequent question people now ask Monto is whether people will need a Covid-19 vaccine "every six months", especially in light of the recently discovered omicron variant. Pfizer recently announced that a third shot of its mRNA vaccine appears to protect as well against omicron as other variants.

"The question is: is this going to be like influenza" - against which an annual vaccine is recommended - "or is it going to be like measles?" - which requires only two doses for life-long protection. "That's where many of us disagree."

Data has shown immunity wanes over time. VRPAC has approved booster shots for all three vaccines, in part to prevent Covid-19 infection, even as mRNA vaccines have shown very good stable protection against hospitalisation and death. Nevertheless, it remains unclear whether three shots will provide lasting immunity against infection.

"We really don't know how well our vaccines will be holding up," he said. Monto said he now believes waning immunity and the continued emergence of new variants, termed "antigen drift", make influenza a useful model for Covid-19 response.

Each year, scientists create a vaccine based on seasonal, circulating variants of the flu virus. Monto said "permanent protection from our current vaccines" is unlikely, making this model a useful basis for future Covid-19 response. And, he said, this is a future we've been apprehensive to consider.

"This is unprecedented, because it's lasted so long," said Monto. By comparison, the jolt of the 1918 influenza pandemic was more acute on a population level, but lasted a shorter period of time.

"It's been difficult to get people to focus on long-term consequences because people have been so wrong already in predictions," said Monto. The virus "continues to create problems".

"Whenever you think things are going to be getting better - because they have already - and are they going to continue to get better, we've had a new surprise," said Monto. "And that's why many people have tried not to think long-term for any extent, because the question then, which is difficult to answer, is: are we going to be back to normal?" And, that question implies a larger one about what the future may look like with masks and social distancing.

Those "non-pharmaceutical" interventions, as scientists call them, are not addressed in Monto's recent article, but he does give us a peek into the meaningful data of the future. Hospitalizations and deaths among people who are vaccinated could become more important metrics than cases alone, as vaccines become a long-term tool to mitigate the worst effects of Covid-19. The development of drugs to treat those infected with Covid-19 will also remain important, particularly if variants impact the efficacy of those already developed, as is the case with monoclonal antibodies.

However, right now, Covid-19 remains a "pandemic of the unvaccinated".

At the time FDA advisors voted in favor of approving the first vaccine, around 285,000 Americans and 1.5m people globally had died. Today, more than 791,000 Americans and 5.2m people globally have died. In the US, many of those deaths immediately post-dated the authorization of vaccines, when they were in short supply. Now, they are widely available, but only 60.4% of the population is fully vaccinated.

"The data are clear: this is a safe vaccine," said Monto. "The data are clear that Covid is a dangerous infection to get, even if you're not older or having underlying conditions, because the outcomes are unpredictable.

"And you may be one of the unlucky ones that gets a severe infection."