The Absolutely True, Incredibly Amazing Story of the Covid-19 Vaccine

As a reporter specializing in vaccines, I knew it was possible — but never thought it would happen quite like this

Tomorrow, it will have been exactly one year since the first Moderna trial began for the groundbreaking mRNA Covid-19 vaccine. Having covered vaccines as a journalist for a decade, never in my wildest dreams did I imagine that less than a year later, I would have two doses of that vaccine in my arm, that it would reduce my risk of catching the coronavirus by 95%, that it would eliminate my risk of death from the disease despite multiple risk factors, and that the worst I’d suffer for it would be a sore arm for a week or so. As a journalist, I’m not supposed to gush over the topics I cover, and I’ve faithfully reported on facts about Covid-19 vaccines without doing so. I’ve been cautious and balanced about what people need to know about their safety and effectiveness and what they do and don’t mean about what we can do while the pandemic rages on.

But a year after that trial began, I have to take a moment and step out of that role to appreciate how incredible the story of these vaccines really is. That whole month of March, and especially that week, was a blur for all of us, as much in Texas (where I live) as anywhere else. SXSW had been canceled 10 days earlier for the first time in its 34-year history. The governor declared a statewide emergency March 13. The first Texan died of Covid one year ago today. The governor would issue the first executive order closing down schools and some businesses four days later. Every other state had done or was doing the same.

And in the midst of all this — long before the full horror of the pandemic would reveal itself — the first U.S. vaccine trial began, the same day that the last U.S. state (Vermont) issued its state of emergency.

Had I not been a reporter specializing in vaccines, I might easily have missed the news. Instead, I was flabbergasted — as much I could be in the midst of every other overwhelming emotion I was feeling. The world had known of the disease less than three months. Never in the history of humanity had a vaccine moved so rapidly from preclinical work in the lab to a human trial.

True, the groundwork for the vaccine had begun years — even decades — earlier. Chinese scientists had sequenced the virus’s genome two months earlier. Three days after the genome was published, Moderna began work on its vaccine, followed by BioNTech/Pfizer almost two weeks later. By mid-February, almost 30 vaccines were in development.

But Donald Trump would not announce the government’s Operation Warp Speed vaccine initiative for two more months still. And I knew the history of every other vaccine ever developed — I’ve literally written a book on it. The fastest before Covid was the mumps vaccine, developed in four years and only because of unfortunate serendipity and the inimitable drive of a scientist, Maurice Hilleman, who developed more vaccines than any other person in history.

Still, I had high hopes. I read everything I could as I followed the story about the vaccines, and when the first trial was announced, I decided to be optimistic. I knew vaccines took 10 to 15 years to develop, and under five years was just about unheard of. Perhaps, I thought, perhaps we could get a vaccine within two years that was at least 70% effective and didn’t have too many side effects. That, I thought, would be as close to a miracle as I’d ever witness.

Yet before the end of 2020, we would have two vaccines, each fully preventing severe illness and death, preventing nearly all (95%) mild and moderate illness, and having an excellent safety profile with little more than typical, familiar — if unpleasant (and sometimes miserable) — side effects. (Anaphylactic reactions are certainly more than unpleasant or miserable — they are life-threatening — but they can also occur with just about any vaccine and are an anticipated, treatable adverse event for any vaccine.)

When I step back and consider all that — which we’ve had little time to do in the midst of the hell of the past year — it’s still hard to wrap my head around the magnitude of that achievement.

Nine months, 95% effective. Wow.

Of course, I can’t think about that without also acknowledging that the incredible speed of Covid vaccines’ development is also — not unreasonably — one of the things that has given some people pause about getting it. I’ve railed against the pointlessness of the unending surveys about Americans’ attitudes toward the vaccine while validating the fact that it’s completely rational to have lots of questions about a new vaccine, and especially one developed so swiftly. Many scientists and science journalists — myself included — had their doubts about whether it was moving too fast (or whether development so fast was possible at all). So we watched attentively to see if corners were being cut, steps skipped, data fudged. By this point, we all had good reason to be suspicious of the government and anything it helped fund.

As the disease infiltrated every corner of the country in huge numbers, it didn’t take long for enough trial volunteers to get sick so that researchers could calculate how effective the vaccines were.

So it was all the more remarkable to me that we reached such a milestone without skipping steps or cutting corners. Two things made that possible. One is obvious: money. The other is ironic: We failed so badly at containing the virus that runaway infections helped the trials fly by.

How did we develop the vaccines so fast without compromising safety or the integrity of the scientific process? It helps to understand how vaccines are normally developed so you can recognize that Covid vaccines went through the same process. All vaccines undergo preclinical work — research and experimentation in the lab before human trials begin. Again, the technology that made the mRNA vaccine possible was nearly a decade old, and three more decades of research before that had started scientists down the right path. Without that crucial foundation, Moderna could never have hit the ground running just days after Chinese scientists had sequenced the virus.

All vaccines then go into phase 1 trials, typically with fewer than 100 people who volunteer to take it so scientists can learn about its safety foremost, and then begin to learn about its possible efficacy. That’s the trial that began March 16 for Moderna. Most often, assuming the phase 1 trial bears fruit, a phase 2 trial doesn’t begin until after phase 1 has been published. That gives time for others to see the data, agree that it’s looking good, and green-light more money for the project. But there were no brakes on funding this time. As soon as researchers and the independent safety review boards overseeing the trials saw that the vaccine was safe and invoked an immune response, phase 2 began with the usual couple hundred people.

But again, it can take months, even years, after a phase 2 trial ends before phase 3 begins, primarily because of holdups on funding and other resources. Yet by mid-summer, phase 3 trials for the Moderna and Pfizer vaccines had begun, enrolling tens of thousands of participants — just like every other phase 3 vaccine trial of the past two decades.

Here’s where the United States’ failure to stop infections sped up the timeline even more. Phase 2 and 3 trials cannot yield data on how effective the vaccine is unless enough people in the placebo group get sick. And most vaccines in development aren’t for diseases tearing through the population at breakneck speed. Yet the United States was failing on an epic scale at preventing coronavirus infections. As the disease infiltrated every corner of the country in huge numbers, it didn’t take long for enough trial volunteers to get sick so that researchers could calculate how effective the vaccines were.

At that point, it was a matter of analyzing the data, submitting it to the FDA, waiting for an independent committee of scientists and health care providers with a verified lack of conflicts of interest to review the data and make a recommendation to the agency, and then for the agency itself to review the data (again) and issue an emergency authorization.

Hard as it is to believe, the nine-month development of Covid vaccines jumped through all the same hoops as any other vaccine in terms of assuring their safety and effectiveness. The abnormal aspect of the trials — how quickly scientists gathered data — was a result of our abnormal reality in which a deadly disease was running wild through our population.

Understandably, some people still worry, primarily about whether long-term effects of the vaccine might emerge years from now. But the only long-term effects that have occurred after licensed vaccines are ones we learned about within weeks or months of vaccination. We learned early on that the oral polio vaccine (not given in the U.S. since 2000) caused paralytic polio (about one per 2.4 million doses). A higher than expected number of Guillain-Barré syndrome (GBS) (a nerve disorder) cases — about one per 100,000 doses — occurred with the 1976 swine flu vaccine.

The manufacturer of the first rotavirus vaccine, RotaShield, voluntarily withdrew it from the market in 1999 after safety surveillance found that it led to about one to two cases of intussusception (a bowel obstruction) per 10,000 infants. (It was RotaShield’s association with intussusception that led researchers to begin including 20,000 to 40,000 people in phase 3 trials instead of several thousands.) And a 2009 H1N1 vaccine given only in Europe — not the U.S. — led to an increased risk of narcolepsy in Sweden. All these issues appeared within weeks or months of immunization and were caught quickly by vaccine safety surveillance systems still in place. If the Covid-19 vaccine caused long-term effects beyond the side effects reported in the trials, we would know about them by now.

Instead, one year after the first U.S. human trials for a Covid-19 vaccine began, one in five Americans has received at least one dose of a Covid vaccine.

A vaccine that was tested for safety and effectiveness as well as any other vaccine.

A vaccine that has not caused any reported death or permanent disability in those who have received it.

A vaccine that prevents death and severe disease in pretty much everyone who gets it.

A vaccine that prevents the vast majority of mild or moderate illness.

That scientific feat alone is nothing short of amazing.

Tara Haelle is a science journalist, public speaker, and author of Vaccination Investigation and The Informed Parent. Follow her at @tarahaelle.

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