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Vaccines might not be the only way to treat COVID-19 | COMMENTARY

In this March 16, 2020, file photo, Neal Browning receives a shot in the first-stage safety study clinical trial of a potential vaccine for COVID-19, the disease caused by the new coronavirus, at the Kaiser Permanente Washington Health Research Institute in Seattle.
In this March 16, 2020, file photo, Neal Browning receives a shot in the first-stage safety study clinical trial of a potential vaccine for COVID-19, the disease caused by the new coronavirus, at the Kaiser Permanente Washington Health Research Institute in Seattle. (Ted S. Warren / AP)

Based on the sheer volume of news coverage alone, it would be reasonable to conclude that it is only a matter of time until one or more vaccines to tame SARS-CoV-2, the virus that causes COVID-19, become available. We disagree. There is no guarantee that such a vaccine will ever be discovered, much less be effective or safe. It is more likely, given advances in the design of antiviral drugs, that a drug (or cocktail of drugs) could sufficiently inhibit the replication of the virus and transform COVID-19 from a killer to a non-newsworthy, easily treatable, mild infection.

Vaccine science is notoriously unpredictable. Despite decades of research, there is still no vaccine to prevent viral infections like HIV/AIDS, hepatitis C, herpes simplex, Zika, West Nile or norovirus (the “stomach flu” that continues to perpetually plague the cruise ship industry).

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Even vaccines that have been successfully developed may have limitations. For example, the annual influenza vaccine is not always effective because of viral mutations and the presence of different flu strains that arise after the vaccine has been manufactured each year. Vaccines are not particularly stable for long periods and must be refrigerated, and they usually take longer to develop and test, whereas most antiviral drugs can be given orally, are shelf stable and typically straightforward to make. Moreover, vaccines are not recommended for certain cohorts of the population such as the very young, those who are immunocompromised, have certain underlying health conditions or those who are allergic to the components in the vaccine. So even if a vaccine is successfully developed, many people will not be able to take it.

While it is always better to prevent an infection than treat it, antiviral drugs for certain infections, namely HIV/AIDS and hepatitis C, are so effective that the former can be held in check at undetectable levels for a patient’s entire lifetime, and the latter can now be cured in 98% of infected patients. Therapies for both of these infections consist of drug cocktails.

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Currently there are 22 FDA-approved drug cocktails available to treat HIV/AIDS that include two, three or even four drugs. This approach has been so successful because it is not possible to completely shut down viral replication with one drug, as the virus will “work around” it. But with two or more drugs it becomes exponentially more difficult for the virus to overcome the effects of the combination.

The use of cocktails is also important because this significantly lowers the chances of a virus developing resistance. Resistance to a drug causes the drug to be less effective or even useless.

While the search for a vaccine continues, scientists are also revisiting many known antiviral drugs, as well as those that are or were previously in development. One of the reasons we are currently scrambling for a cure is that funding for coronaviruses, despite warnings from virologists around the world, was not considered a priority when the two previous coronavirus outbreaks (SARS and MERS) occurred.

Funding agencies such as the National Institutes of Health believed that these were isolated outbreaks since only two had ever occurred, and they didn’t really impact the USA. Clearly that was a fatal mistake. However, we cannot look back — we must look forward and try to find answers to this deadly pandemic, as well as to be better prepared for future outbreaks. In our opinion, that answer could very well be found in small molecule antiviral drugs, not vaccines.

Katherine Seley-Radtke (kseley@umbc.edu) is a professor of chemistry and biochemistry at the University of Maryland, Baltimore County. Josh Bloom (bloomj@acsh.org) is the director of chemical and pharmaceutical science at the American Council on Science and Health in New York.

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