The three key obstacles to eliminating a coronavirus vaccine

First, will it work? Preliminary studies indicate that various types of vaccines currently under development produce a strong immune response. This is good news, but it does not mean that the vaccine will protect people against infection or disease. We do not know whether the immune response is protective and, if so, how extensive that protection will be. (Protection ranges from 0% to 60% for influenza vaccines to 95% or more for some other vaccines.) Even if a vaccine protects against the disease, it may not prevent people from becoming infected and spreading the virus to others.

We also don’t know whether all people will be protected by a new vaccine, particularly older people, who have a markedly higher risk of Covid-19 and are less likely to have a strong immune response. We also don’t know how long a protection will last. We don’t even know how protective the natural Covid-19 infection is; For many vaccines, the degree of immunity to natural infection is the limit of their potential effectiveness.

Still, we have every reason to be cautiously optimistic that some vaccines will provide some level of protection, and that this will be demonstrated before the end of 2020. Some vaccine candidates may be fraudulent, and the effectiveness of others may decrease in just a few months. . “Something that, of course, will take many months to know.” Different vaccines may be more or less effective, and some vaccines may work less well for some groups. And most vaccines never get approved; Many of today’s promising candidates may fail. We just don’t know. That’s what studies are for.

Second, will it be safe? What could go wrong with the new vaccines? Much. Several candidate vaccines use a harmless virus as a “vector” to deliver the antigen. This technology is promising, but we have limited experience in its use. And we’ve never used DNA or RNA vaccines, the technology used for several developing Covid-19 vaccines, in humans.

We now know that a small proportion of children who get Covid-19 get a life-threatening inflammatory condition as their immune system reacts to the coronavirus. A vaccine could, on rare occasions, create a similar immune storm that causes severe illness, particularly in children, either from the vaccine itself or from subsequent exposure to the virus. There is no particular reason to believe that Covid-19 vaccines cause this type of overreaction, but it is a risk and should be studied, both before and after approval.

Polio vaccination offers a warning story. Shortly after the vaccine was invented, a manufacturer contaminated a batch of the vaccine and many children were paralyzed. In 1976, when an outbreak of H1N1 influenza in Fort Dix, NJ, raised concerns about a pandemic, President Gerald Ford led the effort to vaccinate tens of millions of Americans. But the dreaded pandemic never materialized, and the vaccine paralyzed more than 500 people, some of whom had life-long problems as a result.

Despite these rare and unfortunate episodes, the vaccines remain surprisingly safe: Billions of doses are administered to people around the world each year, with very few problems. However, adverse vaccination events may not be apparent until hundreds of thousands or millions of people have been vaccinated, so there can be no shortcuts to safety. Humility is in order.

Third, can we take it to people? Even if we can develop an effective vaccine with a reassuring initial safety record, can we get it to people? Vaccine manufacturing is not simple. Failures or contamination can occur, even with experienced pharmaceutical companies, and not all companies that make the new vaccines have experience.

And even if an effective, seemingly safe vaccine is produced in large quantities, it will be difficult to distribute it quickly and equitably, store and ship it at the right temperature, educate doctors and inform communities, and monitor absorption and possible harmful side effects. . . The protection that even a highly effective vaccine provides is as good as our delivery systems. Measles vaccine is more than 90% effective, but the World Health Organization reports that more than 140,000 children died from the disease worldwide last year, most of them in communities with low vaccination rates. .

The biggest challenge in getting a Covid-19 vaccine in the arms of enough people will not be scientific, technical, or logistical; will come for lack of confidence. Particularly this election season, the vaccine evaluation process must be scientifically rigorous and open. Public confidence can be eroded by large profit margins for vaccine manufacturers, lack of transparency about cost of production, and prices that do not take into account the fact that many vaccines benefit substantially from funded research. public. Open meetings of the key advisory committees of the Food and Drug Administration and the Centers for Disease Control and Prevention will be indispensable.

We must level out with the American public in a way that was not done during this pandemic. We don’t have enough evidence, so we must prioritize. We do not have enough protective equipment for healthcare workers, so we must safely produce reusable N95 masks. And when vaccines arrive, we won’t have enough for everyone. Different vaccines may be available at different times, and some will probably work better than others. Governments should establish priorities among different groups, considering factors such as the risk of serious Covid-19 disease, the protection of essential functions and equity. Workers in jails, nursing homes, and hospitals, for example, and black and Hispanic people are more likely to be exposed to the virus and have underlying health conditions that make them particularly vulnerable.

Furthermore, vaccines will not provide perfect protection and will probably not completely end the pandemic. In our interconnected world, a truly global vaccination campaign will be essential to America’s long-term health and economic recovery.

Even within the United States, unless the vaccine is remarkably effective and accepted, cases and groups will continue, requiring rapid and effective public health responses. Our society will still have to adapt to limit the spread of the virus: reduce close indoor contact, avoid handshakes, wear masks, and improve ventilation. And unless the vaccine is surprisingly potent or we discover highly effective treatments, my 91-year-old mother will not be returning soon to her beloved choir practices.

Implementing a Covid-19 vaccine is the most important thing we can do to restore order and normality in our world. We cannot afford to be wrong.

-Dr. Frieden was director of the CDC from 2009 to 2017. He is president and CEO of Resolve to Save Lives (an initiative of the public health organization Vital Strategies) and a senior member of the Council on Foreign Relations.