As we emerge from four years of “it’s going to be great because I say so,” Americans have hopefully learned an important lesson about checking sources and questioning what we are told. Although Donald TrumpDonald TrumpJan. 6 committee chair says panel will issue a 'good number' of additional subpoenas Overnight Defense & National Security — Presented by AM General — Pentagon officials prepare for grilling Biden nominates head of Africa CDC to lead global AIDS response MORE won’t be president much longer, multiple arms of the Department of Health and Human Services continue to work on Trump’s Operation Warp Speed, whose multibillion-dollar “goal is to produce and deliver 300 million doses of safe and effective vaccines with the initial doses available by January 2021.”
While Americans understandably want a vaccine soon, we must be cautious about the motives behind — and perils of— any rush to market from pressure by the current administration. Good science takes time. With government investments of $26 billion in grants and funds that have been provided to the U.S. for COVID relief, this week’s announcement by Pfizer that a vaccine looks promising and that it is 90 percent effective is cause for celebration. So, 90 percent of what?
For certain, Covid has resulted in an extraordinary number of deaths (almost a quarter of a million in the United States alone), decimated the global economy, and changed how we live, very likely forever. Such extraordinary circumstances, many may feel, call for extraordinary measures. Yet if a vaccine is distributed before adequate safety data are collected, people could die needlessly. If a vaccine is distributed before, at least minimal efficacy data is available. The real risk is a false sense of security where people prematurely abandon other effective countermeasures, such as masks and social distancing. More people could be infected than would otherwise have been.
Even in the best-case scenario, there is no chance that the vaccine will be absolutely safe and effective, and vaccines can be less effective in the setting of lots of diseases. Besides, viruses can mutate, decreasing the impact of a vaccine. For example, the flu vaccine is typically less than fifty percent effective. SARS, the virus family to which COVID belongs, is known to mutate, increasing its infectivity.
The path to vaccine approval is initially based on safety and, as long as there are no or only rare life-threatening reactions, a vaccine can move forward into clinical trials. Scientists have been making vaccines since 1796, when Edward Jenner developed a vaccine from milkmaids who had contracted cowpox and were thus protected against smallpox. The path is now well marked for infectious disease.
The Pfizer vaccine has been given to some of the more than 43,000 people in the study without detectable side effects, so safety appears quite good. In Pfizer’s trial, volunteers were treated with either saline as a placebo or the COVID vaccine. When the company reports that it is 90 percent effective, 90 percent fewer people were infected. In this case, Pfizer’s trial endpoint is 164 cases of COVID (almost 100 have been so far), which means that we expect the final count to be around 15 infected in the vaccine group and 145 in the control group (that’s a 90 percent difference).
It is unclear what other factors were controlled for in Pfizer’s study, nor do we know the ratio of vaccinates to controls. In a sea of over 43,000 people, could 130 people have had a different risk level than others? Did all participants use all countermeasures? Were they actually at risk equally in both groups and all demographics? If more people in the placebo group went to the grocery store and more people stayed home in the vaccine group, we could see a difference between groups related to factors other than the vaccine. This infectivity rate of less than 1 percent is below the national average (number of people infected in 2020) of 2 to 3 percent so, who are these volunteers? We also don’t know whether the vaccine actually keeps you out of the hospital or decreases the risk of death. It will take more time to accumulate this information. The tricky part is that the ideal test of a vaccine is a challenging study and we can’t do those on ethical grounds. This would require you to be vaccinated and then someone who is known to be shedding the COVID virus coughs in your unprotected face. We then watch to see if you become infected and get sick. And we repeat that test hundreds or thousands of times. Instead of such a horrific thought, we look for trends in infection rates as a surrogate endpoint.
There are many countermeasures to controlling COVID while we await the arrival of a safe and effective vaccine. Certainly, mask-wearing (easy to do, helps many, hurts none), hand washing (easy to do, helps many, hurts none), social distancing (harder to do because we are social creatures, helps many, can hurt businesses), and testing (increasing availability, easy to do, who pays? helps many, hurts none) all play a role. Unfortunately, there is something more contagious than COVID: habits. So, wear a mask.
The race to find a vaccine for COVID involves both science and commercialization. These are inextricably linked to big pharmaceutical companies. Thirteen other companies are approved to work on COVID vaccines and four are in phase 3 trials, close behind Pfizer. Each vaccine is different; for example, the Pfizer protocol involves two vaccines, whereas the Johnson&Johnson involves one. My plea is three-fold: be patient and let scientists do their job well, then question what you are told to be sure you understand the context and remember that a vaccine is not a panacea. Continue to use all available countermeasures. In an era of information overload and instant gratification, it’s easy to hope for results that push the limits of science. We can’t exceed them.
Kim Selting, DVM, MS, is an associate professor in the Department of Veterinary Clinical Medicine at the University of Illinois in Champaign Urbana. Dr. Selting is a Public Voices fellow of The OpEd Project and heads the Veterinary Teaching Hospital's radiation therapy program.