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The three main obstacles to clearing a Coronavirus vaccine



Vaccines have transformed the world, saving hundreds of millions of lives. They are also by far our best hope to stop the Covid-19 pandemic. Our other choices to stop the disease are staying away, which blocks our economy and society, or building “herd immunity” through natural infection, which would mean more than one million deaths in the US and 10 million or more deaths worldwide. But pushing for a Covid-19 vaccine faces three major hurdles.

First, will it work? Preliminary studies show that some types of vaccines now in 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 if the immune response is protective, and if so, how broad that defense will be. (Protection ranges from 0% to 60% for influenza vaccines to 95% or higher for some other vaccines.) Even if one vaccine protects against disease, it cannot prevent people from becoming infected and spreading the virus to others. .

We do not even know if all people will be protected from a new vaccine ̵

1; especially the elderly, who have a significantly higher risk of Covid-19 and may be less likely to have a strong immune response. . We also do not know how long any protection will last. We do not even know how protective the natural Covid-19 infection is; for many vaccines, the measure of immunity to natural infection is the ceiling of their potential efficacy.


We do not know if all people will be protected by a new vaccine.

We still have ample reason to be optimistic that some vaccines will offer some level of protection, and that this will be demonstrated before the end of 2020. Some vaccine candidates may be dud, and the efficacy of others may wane. within just a few months This thing, of course, will take many months to get to know. Different vaccines may be more or less effective, and some vaccines may work less well for some groups. And most vaccines never do it for approval; many of today’s promising candidates may fail. We just do not know. This is what studies are about.

Second, will it be safe? What could go wrong with new vaccines? More. Some candidate vaccines use a harmless virus as a “vector” to deliver the antigen. This technology is promising, but we have limited experience using it. And we have never used the DNA vaccines or RNA technology used for some Covid-19 vaccines in development – in humans.

We now know that a small proportion of children who contract Covid-19 get a potentially life-threatening inflammatory condition as their immune system reacts to the coronavirus. A vaccine can, in rare cases, create a similar immune storm that causes serious illness, especially 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 will cause this type of overlap, but it is a risk and should be studied, both before and after approval.

Jonas E. Salk (1914-95), the American physician who developed the first effective polio vaccine, inoculating a child as a nearby nurse, ca. 1955.


photo:

Everett Collection

Polio vaccination provides a warning story. Shortly after the vaccine was invented, a manufacturer contaminated a batch of vaccines and many children became paralyzed. In 1976, when an H1N1 flu outbreak in Fort Dix, NJ, sparked concern about a pandemic, President Gerald Ford led the effort to vaccinate tens of millions of Americans. But the fear pandemic never materialized, and the vaccine paralyzed more than 500 people, some of whom had lifelong problems as a result.

Despite these rare and unfortunate episodes, vaccines are still surprisingly safe: Billions of doses are given to people all over the world every year, with very few problems. However, adverse events from vaccination 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 fine.

Third, can we reach people? Even if we can develop an effective vaccine with an initial safety record, will we be able to bring it to humans? The production of vaccines is not simple. Failures or contamination can occur, even with experienced pharmaceutical companies – and not all companies that make new vaccines are experienced.

And even if an effective, seemingly safe vaccine is produced in large quantities, it will be difficult to distribute it quickly and evenly, store and deliver it at the right temperature, educate physicians, and inform communities. and monitor potential harmful acquisition and capabilities. The protection provided by a highly effective vaccine is just as good as our delivery systems. The measles vaccine is more than 90% effective, but the World Health Organization reports that more than 140,000 children died of the disease worldwide last year – most of them in low-vaccination communities.


Especially in this election season, the vaccine evaluation process should be scientifically rigorous and open.

The biggest challenge to getting a Covid-19 vaccine in enough human arms will not be scientific, technical or logistical; will come from lack of trust. Especially in this election season, the vaccine evaluation process should be scientifically rigorous and open. Public confidence can be eroded by large profit margins for vaccine manufacturers, lack of transparency regarding production costs, and prices that do not take into account the fact that many vaccines benefit significantly from publicly funded research. Open meetings of the main advisory committees of the Food and Drug Administration and the Centers for Disease Control and Prevention will be necessary.

We need to level up with the American public in a way that was not done during this pandemic. We do not have enough tests, so we have to prioritize. We do not have enough protective equipment for healthcare workers, so we need to produce reusable masks safelyN95. And when vaccines arrive, we will not have enough for everyone. Different vaccines may become available at different times, and some will probably work better than others. Governments will have to prioritize between different groups, taking into account factors such as the risk of serious Covid-19 disease, the protection of essential functions, and justice. Workers in prisons, nursing homes and hospitals, for example, and Black and Spanish people are more likely to be exposed to the virus and have basic health conditions that make them particularly vulnerable.

Moreover, vaccines will not provide perfect protection and may 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 US, unless the vaccine is extremely effective and accepted, cases and clusters will continue, seeking prompt, effective public health responses. Our society will have to adapt to limit the spread of the virus – by reducing close contact indoors, holding hands, wearing masks and improving ventilation. And if the vaccine is surprisingly powerful or we do not discover very effective treatments, my 91-year-old mother will not soon return to her beloved choir practices.

Deploying a Covid-19 vaccine is the most important thing we can do to restore order and normalcy in our world. We can not afford to mistake it.

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