Hopes are running high that a coronavirus vaccine will be ready by the end of the year But It Probably Won’t Stop Pandemic. But some scientists caution that the hype might be outpacing the reality.
The first COVID-19 vaccine likely won’t be effective enough to end the global pandemic, vaccine experts say. Instead, we may live with the virus for years before a winning one emerges.
In July, the first large-scale human trial of two coronavirus vaccine candidates will start, according to US health officials, who are sounding increasingly confident that some kind of vaccine will be ready to be distributed widely by December.
“I’m cautiously optimistic that with the multiple candidates that we have with different platforms that we’re gonna have a vaccine,” said National Institute of Allergy and Infectious Diseases chief Anthony Fauci, speaking on Tuesday at a briefing held by the Journal of the American Medical Association (JAMA). He predicted that nearly 100 million doses of a successful vaccine would be available by November or December, and perhaps 200 million doses by the beginning of 2021, largely due to taxpayer and philanthropic investments in factories that will be built to manufacture the massive quantity of vaccines.
The White House’s Operation Warp Speed is expected to name five companies — Moderna, AstraZeneca, Johnson & Johnson, Merck, and Pfizer — to lead the vaccine effort in the US, according to the New York Times.
Vaccines essentially imitate an infection — without getting you sick — training your immune system to quickly produce antibodies to repel a real attack. The biggest hope for a vaccine came after a May study showed that nearly everyone who recovers from COVID-19 produces antibodies to the coronavirus, also called SARS-CoV-2, meaning that the virus can be fought with vaccination. “That’s a pretty good proof of concept to say that you’re going to make an immune response in response to a vaccine,” said Fauci.
But what makes a successful vaccine? The first ones to emerge from the 10 candidates now being tested in people worldwide are likely to resemble the seasonal flu shot. These vaccines need to be administered year after year and are sometimes only around 30% effective at blocking an infection, while at the same time promising milder symptoms to people who do get sick. That’s in stark contrast to other vaccines, like the one for measles, where two shots confer immunity for a lifetime.
“When people talk about the race for the COVID-19 vaccine, I have to say, ‘Be careful what you wish for,’” said vaccinologist Peter Hotez of the Baylor College of Medicine. “History tells us that the first ones have a built-in obsolescence.”
Along with the 10 SARS-CoV-2 vaccines now in human trials, more than 120 others are under study in test tubes and lab animals, according to the World Health Organization. Each one aims to, hopefully, produce enough of the right “neutralizing” antibodies to prevent future infections. The trials take two groups of study volunteers, randomly picked to either get a real vaccine or a placebo, and then measure for differences in how many people get infected or have severe symptoms.
Broadly speaking, the candidates work by four methods, only two of which have long been proven to work in past vaccines. The first is to give people a weakened or killed form of an actual virus, used in polio, chicken pox, and flu vaccines. The second proven way is to just inject a small fragment of the virus to trigger immune readiness, like the HPV vaccine or newer flu vaccines.
A third cutting-edge approach is under study by AstraZeneca and the University of Oxford, whose vaccine is expected to enter a large human trial in July. It works by taking a chimpanzee virus and coating it with the tiny spikes that cover the surface of SARS-CoV-2. The chimp virus causes a harmless infection in humans, but the spike proteins will prime the immune system to recognize signs of a future SARS-CoV-2 invasion.
That’s in theory. “There isn’t a guarantee ever that you’re going to get an effective vaccine,” said Fauci. The US Biomedical Advanced Research and Development Authority has provided more than $1 billion for the Oxford vaccine’s development, and AstraZeneca has announced a plan to test the candidate in more than 10,000 people in the United Kingdom. But Stop Pandemic in early data, the vaccine has underwhelmed observers, who noted it didn’t prevent infections in monkeys, just lessened their symptoms. William Haseltine, a former Harvard Medical School professor known for pivotal research on cancer and HIV, noted the neutralizing antibodies produced by the vaccines were “extremely low,” in Forbes.
“Time will tell if this is the best approach,” Haseltine concluded. “I wouldn’t bet on it.”
The fourth approach is a genetic vaccine, where only the genes that cells need to produce the coronavirus spike are injected into a person. Those spike proteins, dutifully produced by cells in response to the genes, alarm the immune system and should produce immunity.
One genetic vaccine that’s emerged as a Wall Street favorite is being developed by a company called Moderna. Expected to begin large-scale human trials by July under Operation Warp Speed, the company has dismayed scientists Stop Pandemic by only releasing press releases with sparse data on its small safety experiments in people, feeding hype about its vaccine candidate.
The only vaccine that has published strong results — albeit only in monkeys and other lab animals — is from China’s Sinovac biotech firm, which relied on the old-fashioned method of injecting a small amount of dead viruses to prime the immune system against a real infection. “That’s an old-school vaccine,” said Hotez. “We do know those work.”
Without the full data measuring the effects of the vaccines in people, however, outside experts tend to be skeptical of their ability to prevent an infection Stop Pandemic. Vaccine experts prefer candidates to be at least 70% effective at preventing infections, Paul Offit of Children’s Hospital of Philadelphia said at a separate JAMA briefing on Monday. Still, even if the vaccine only lessens the severity of a deadly disease, he added, that “would be great, because it keeps you out of the hospital, it keeps you from dying.”
The two Operation Warp Speed candidates will begin human trials in 30,000 people in the first week of July, Fauci said. In these trials, happening largely in the US but also overseas, some volunteers will randomly receive an inoculation and others will receive a placebo. These studies are at the mercy of the size of the outbreak where they take place, because you need enough people in the placebo group to become infected to know the vaccine is working.
If the trial locations don’t have a high rate of infections, “it could take months and months and months to get an answer,” said Fauci. On the other hand, if the trials take place amid a big surge in cases, “you could get your answer pretty quickly.”
With infections continuing but not spiking nationwide, likely due to people continuing to follow physical distancing measures, there’s a real concern that the clinical trials could stretch out for months. If this happens, typically trials Stop Pandemic have to add more participants, causing delays. A 2006 rotavirus vaccine trial in 40,000 children grew to more than 70,0000 for that reason, said Offit, and stretched out for more than three years. “It’s hard to study something that doesn’t happen.”
That might easily delay a vaccine past December. Ken Frazier, the CEO of Merck, one of the firms reportedly selected for the Warp Speed trials, told the Financial Times in May that the 12- to 18-month timeline the program called for was “very aggressive” and set an unrealistic standard for his company.
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