Nearly $ 6 billion has been allocated. Clinical trials are entering a crucial third phase, and Operation Warp Speed is approaching the goal of delivering 300 million doses of a COVID-19 vaccine by January.
But when Americans line up to get their shots, the shot they get may not be what they expect. The popular notion of a vaccine, an injection in the arm that prevents diseases like measles, polio, or herpes zoster for years or a lifetime, may not apply.
According to recently released federal guidelines, the use of a COVID-19 vaccine can be authorized if it is safe and effective in only 50% of those who receive it. And “effective” does not necessarily mean preventing people from getting sick from COVID-19. Experts say it means minimizing your most severe symptoms.
“We must anticipate that the SARS-CoV-2 vaccine will be similar to the influenza vaccine,” said Dr. Kathleen Neuzil, director of the Center for Vaccine Development at the University of Maryland. “That vaccine may or may not prevent people from becoming infected with the virus, but it keeps people out of the hospital and ICU.”
Even with low expectations, the development of a vaccine against a virus that nobody knew about seven months ago is considered remarkable. One evaluation calls it “compressing six years of work into six months.”
Of the more than 150 vaccines in process worldwide, Operation Warp Speed has identified 14 “promising candidates.” (A vaccine developed by El Segundo-based ImmunityBio, led by Times owner Dr. Patrick Soon-Shiong, is among 14. It has not yet been tested in humans.)
Of those 14, seven have been designated as favorites, including three whose first clinical trial results have been independently evaluated.
The vaccine developed by Moderna and the National Institutes of Health was deemed “promising” in an editorial published in the New England Journal of Medicine, and two studies in The Lancet conveyed a similar message for vaccines being developed at the University of Oxford. and in China. CanSino company.
These vaccines have induced an immune response in people who participate in early tests, but inducing an immune response does not always mean success in fighting a disease. For example, scientists recently developed a vaccine for another respiratory virus that raised antibodies, but their phase 3 clinical trial failed.
While there is no way to predict what’s ahead, experts say, the first round of COVID-19 vaccines will likely not eliminate the need for other public health measures, such as masks and social distancing.
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The minimum 50% efficacy recommendation set in late June by the Food and Drug Administration would likely ease the burden on hospitals. And to the extent that a COVID-19 vaccine prevents infection, it could reduce the spread of the virus and help create pockets of immunity across the country, said Dr. Peter Hotez, dean of Baylor College’s National School of Tropical Medicine of Medicine.
“Ideally, you want an antiviral vaccine to do two things,” said Hotez. “First, reduce the likelihood of becoming seriously ill and going to the hospital, and two, preventing infection and therefore interrupting disease transmission.”
In this case, he added, “the bar doesn’t seem that high.”
Developing a vaccine capable of inducing “sterilizing immunity,” that is, the ability to prevent the virus from causing an infection, takes time and research, which may not be possible as death tolls continue to increase and the recession. deepens. However, with so many companies on the hunt for that vaccine, there is hope that one of them can get it.
Dr. Mark Feinberg, CEO of the International AIDS Vaccine Initiative, cites the success of the Ebola vaccine. Not only did it accelerate its clinical trials, from starting Phase 1 to obtaining early Phase 3 results in 10 months, but it was also almost 100% effective within 10 days of single-dose administration.
That is probably not the case now. “The challenge is that the new coronavirus has not been around long enough,” said Feinberg.
The scientists had studied other coronaviruses – SARS and MERS – and mapped the genome of the new coronavirus not long after the first COVID-19 deaths were recorded. They identified the spike protein in the virus’s outer coat, which the virus uses to infiltrate the host cell, and created a three-dimensional model of the virus to see how antibodies block infection by binding to the spike protein.
Still, scientists still don’t know what immunity to the virus looks like. That information generally comes from studying the body’s natural response to disease. The number of neutralizing T cells and antibodies that fight an infection can become a model for a vaccine.
But the new coronavirus is not easily revealing those secrets.
Doctors have noted a wide range of immune responses to COVID-19, Feinberg said. Some patients produce high levels of neutralizing antibodies, while others produce only low levels.
“The interesting thing is that everyone has recovered, and we don’t know how they did it,” said Feinberg, former head of public science and public health at pharmaceutical giant Merck.
Scientists are also not sure how long immunity lasts, from a natural infection or a vaccine, and whether a decrease in antibodies in two to three months is cause for concern.
The third phase of clinical trials could answer some of these questions. Moderna is enrolling 30,000 people for its Phase 3 trial, which started Monday.
“If we get a vaccine that is 60% effective, we can use the information to identify what distinguishes people who are protected from people who are susceptible,” Feinberg said. “Then we will know what the minimum target is for an immune response.”
But the absence of that information does not prevent the distribution of a vaccine. Many vaccines are effective even though scientists do not know the amount of antibodies needed to prevent infection. A vaccine can even be effective if it does not prevent infection.
The polio vaccine that Jonas Salk developed does not prevent the polio virus from infecting the gastrointestinal tract, Feinberg said, but it prevents the virus from traveling to the central nervous system where it causes the worst symptom of the disease, paralysis.
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With so many questions still unanswered, the effectiveness of a COVID-19 vaccine may not be known until long after Americans have received their vaccines.
Among the recommendations in the FDA guidelines is a provision for authorization of emergency use, which allows the distribution of a vaccine if “the known and potential benefits of a product … outweigh the known and potential risks of the product” .
“I imagine that the FDA is likely to issue an emergency use authorization if any of the vaccines in development show significant and compelling evidence of efficacy and safety,” said Feinberg, whose research organization is collaborating with Merck to develop a COVID- 19. vaccine.
Under an emergency use authorization, the vaccine could be administered before the completion of Phase 3 trials, which could help flatten the curve but give scientists little time to study side effects or understand how it interacts with other vaccines. .
Dr. Paul Offit, a vaccine expert at Children’s Hospital of Philadelphia, has expressed concern that the FDA authorizes the manufacture and distribution of vaccines before the necessary reviews are completed.
Offit fears that a vaccine with limited efficacy delivered prematurely could give people “a false sense of protection” and “lead to serious outbreaks of the disease.”
“We should wait for the completion of the Phase 3 trials, no matter how long they take,” he said. “Hopefully, they could finish in six to nine months.”
But postponing the delivery date of a vaccine would not align with Operation Warp Speed’s January goal.
The Trump administration’s ambitious timeline has led to $ 5.7 billion being allocated to seven companies, and critics like Hotez and Offit wonder if speed gets in the way of science.
Dr. Robert Gallo, director of the University of Maryland Institute for Human Virology, argues that Operation Warp Speed, a public-private partnership, is “science by committee” led by some people, when there needs to be strong debate and exchange of information.
“If science problems need innovation, then there must be ample opportunities for original thinking and a means to argue or counter without concern that it cannot be funded,” he said.
Gallo, co-founder of the Global Virus Network, is concerned that the seven leaders of Operation Warp Speed are using the same strategy for their vaccine, one designed to neutralize the spike protein.
If that method is ineffective, then the period for administering a vaccine will be extended.
“I am sure it is not advisable to put all these eggs in one basket,” he said.
