Scientists around the world are working towards effectively managing the COVID-19 pandemic. Developments are being made daily as we learn more about this virus. A team at the Harvard T. H. Chan School of Public Health is tracking these developments in fourteen priority areas at covidpathforward.com. Here are five key developments to watch, as of mid-July 2020.
There are thirty vaccines currently in phased trials and over 100 in preclinical trials around the world. Just a few months ago, scientists were not sure if a vaccine would be possible for this virus, and the twelve- to eighteen-month timeline for development would be the fastest ever for a vaccine. Now, early results indicate that there will be an effective vaccine for SARS-CoV-2, and it may be ready by the end of 2020. Moderna is currently testing a new type of vaccine, called a messenger RNA vaccine, that researchers hope will help the body produce antibody proteins against the virus. CanSino Biologics is testing a more traditional vaccine type, a non-replicating viral vector, that researchers hope will deliver coronavirus antigens into the body that create an immune system response against the virus. Importantly, though, once an effective vaccine is ready, it still needs to be manufactured and distributed. “At-risk” manufacturing, conducted while the vaccine is still in clinical trials in order to speed up production and distribution should the vaccines prove safe and effective, is currently underway for several vaccine candidates. Also, a vaccine that prevents infection is the most desirable outcome, but vaccines that instead prevent illness or decrease the severity of symptoms can also save lives and reduce the risk of overwhelming the healthcare system with critically ill patients.
While vaccine research often receives more media attention, therapeutics are vital to the COVID-19 response, as they have the potential to lower hospitalization, death, and transmission rates. Dexamethasone, a steroid used to treat rheumatoid arthritis and asthma, has been shown to reduce death for people infected with COVID-19 who have severe symptoms, such as those on a ventilator, and is already in widespread use. Other researchers are studying “monoclonal antibody drugs,” which recognize a specific protein on the surface of the virus. These drugs have the potential to be used either as a treatment or as a temporary prevention method. Regeneron has developed a monoclonal antibody drug that is currently entering Phase III trials.
While COVID-19 tests have already been developed and are being used, they could be improved upon in terms of speed and ease of use. The “PCR testing” that is currently used looks for the genetic material of the virus in a person’s nose or throat mucus. It is generally the most reliable coronavirus test currently available, but it requires a trained professional to perform the test. Additionally, PCR tests must be sent to a lab for analysis in order to receive the results, which takes several days.
Another type of test, known as antigen testing, would allow faster results and would not need to be performed by a trained professional. Antigen tests look for proteins on the virus instead of the genetic material itself. Currently available antigen tests are less reliable than PCR tests. New scientific evidence, however, supports the development of a reliable antigen test that would allow any individual to test themself using their saliva and to have a result in only twenty minutes. An additional benefit to this type of “rapid testing” is its low cost, estimated to be under $10 per test. Should this type of inexpensive and reliable rapid test become available, it might be considered for use by theaters.
More and more scientists have found that airborne transmission plays a key role in the spread of COVID-19. Recently, 239 scientists sent an open letter to the World Health Organization calling for the organization to revise its recommendations to include this transmission method. The letter cited a large body of evidence that SARS-CoV-2 is present and infectious in small airborne droplets. In response, the WHO updated its guidelines to include the possibility of airborne transmission indoors, in crowds, or in poorly ventilated spaces. The significance of airborne transmission reinforces the need for mask wearing and Healthy Building controls such as ventilation and filtration of indoor air to reduce the risk of viral transmission.
Cross-Reactivity in T Cells
Recent research suggests that some people who have not been exposed to SARS-CoV-2 may have immune cells, particularly memory T cells, that react to the virus. Memory T cells recognize an infection that an individual has been exposed to before and help to activate a fast, strong immune response. When they react to a virus that they have not been previously exposed to, they are said to have cross-reactivity. While the people with these reactive T cells, who make up 20-50% of the population, have not previously been exposed to the novel coronavirus, the source of their reactive T cells may be prior exposure to other coronaviruses, such as those that cause the common cold. Scientists do not yet know whether these individuals’ T cell reactivity will offer any protective benefit against SARS-CoV-2 or will impact their likelihood of transmitting the virus, but research into these questions is ongoing.