COVID-19: The Science
Behind the Headlines

By Dr. Bob Brennan, Jr.

Biology Department chair and professor
Posted: May 29, 2020

 

Like you, I have seen or heard many of the daily headlines regarding the COVID-19 pandemic, but we do not often hear about the science behind the headlines. This can leave the audience scratching their heads with unanswered questions or developing skepticism about what they are hearing. For example, what is going on with testing, why don’t we have treatments, and why can’t we have a vaccine sooner? As a microbiologist with over 25 years of studying infectious disease, diagnostics, infection prevention, and vaccines, I am happy to provide some insight about these topics.

 

Since this illness (COVID-19) is caused by a virus, some explanation of what viruses are in general is warranted.  COVID-19 is the disease caused by a virus identified as SARS-CoV-2, similar to how AIDS is a disease caused by HIV. Viruses are small obligate intracellular parasites, meaning that they can’t replicate on their own and can only replicate when they are inside of a host cell. There are viruses that infect people, viruses that infect animals, viruses that infect plants, and viruses that infect bacteria. They have very simple anatomy. They are composed of either RNA or DNA and surrounded by a protein coat. Some have an extra lipid layer. This virus has an RNA genome, a protein coat, and is surrounded by a lipid envelop. 

 

Every day we are updated on the number of infections and numbers of fatalities, which unfortunately, we have now surpassed 100,000 COVID-19 related deaths. Infection risk is in part, directly related to how this virus is spread. The main route of transmission is through respiratory droplet/airborne. When someone coughs or sneezes, respiratory droplets are expelled at more than 100 mph and can travel several feet. The big drops do not travel as far, but the very fine droplets do and can remain suspended in the air for longer periods of time. Particularly concerning with this virus is asymptomatic and presymptomatic shedding, which makes it harder to control because you cannot identify infected people as readily, which is critical to isolation and contact tracing.

 

The current “gold standard” for the identification of infected people is a molecular test that amplifies target genetic material specific to the virus. It is a complex test, that requires an expensive instrument, expensive reagents, designated laboratory facilities, and specially trained technical personnel to run the assay, all of which have contributed to the lack of widespread testing. Antibody tests have also been discussed more recently. The objective of antibody testing is to identify individuals who have been exposed to the virus and could now have some level of immunity to the virus and potentially serve as plasma donors.

 

Several treatments for COVID-19 have been or are currently being investigated. The majority of the evidence shows that hydroxychloroquine, which is an approved treatment for malaria, is not a safe and effective treatment for COVID-19 patients. Remdesivir, which is an antiviral drug, has shown some promising preliminary results, but additional clinical data is needed. The possibility of using donor plasma to treat critically ill patients is being investigated as well. The concept here is that when people recover from COVID-19 infection, they will have antibodies in their plasma that can be given to other people to reduce the severity of the illness and aid in recovery. There is a precedent for this. This technique was first demonstrated back in the late 1800s in the treatment of people infected with Diphtheria and is still a treatment option for people afflicted with tetanus and rabies. Plasma therapy was successfully used in the treatment of SARS and MERS infections with satisfactory efficacy and safety. It remains to be determined if this technique will be broadly effective for COVID-19 patients.

 

The development of a safe and effective vaccine has been touted as the only way we will be able to get back to or normal way of living, which may or may not be entirely accurate. Some scientists are cautiously optimistic that we may have such a vaccine by the end of the year. Vaccines for new pathogens often take years to develop. The process involves identifying what part(s) of the pathogen, in this case, the virus, stimulate(s) a protective immune response, which can take a couple years. Fortunately, because this virus is closely related to the SARS and MERS viruses, scientists have a head start on this part. Next is to choose a strategy. Will the vaccine be an attenuated virus, an inactivated virus, parts of the virus, DNA based, or RNA based? As of today, there are vaccines studies being conducted on just about every strategy.  Evaluation of these strategies usually begin with animal testing (mice, rats, monkeys) and then move to human clinical trials if they show promise in animal models. The series of phase I, phase II, and phase III clinical trials can take several years to demonstrate safety and efficacy, establish dose schedule, and build large scale manufacturing and distribution. In this case, some of the vaccine developers have gone ahead and started to scale up manufacturing capabilities to be ready if a vaccine does prove to be safe and effective, which could save a couple of years in getting a vaccine into widespread availability.

 

Until there is a safe, effective vaccine and proven treatments for COVID-19, continuing behavior modification is the most effective way to reduce our risks of contracting or spreading the virus. Wearing of masks in public spaces, practicing good hand hygiene, disinfecting high contact surfaces regularly, minimizing gathering sizes, and maintaining social distancing are all helpful methods to reduce the spread.

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