Q&A with Dr. Chip Schooley on How SARS-CoV-2 Spreads, Vaccine Trials Underway and More

UC San Diego’s fall plan is continually evolving, informed by the university’s Return to Learn program. We invited students, faculty and staff to submit their questions about how the university is involved in vaccine development, how the SARS-CoV-2 virus spreads, the importance of wearing masks and more.

To address several of these important topics, we spoke with Dr. Robert “Chip” Schooley, a professor in the Department of Medicine at UC San Diego School of Medicine and a leader of UC San Diego’s Return to Learn program.

Q. How is UC San Diego involved in national clinical trials for a COVID-19 vaccine?

A. UC San Diego is involved in three national trials to protect against SARS-CoV-2, the novel coronavirus that causes COVID-19. These are phase III clinical trials, which means we are evaluating the effectiveness of the vaccine. Each of these trials will have more than 10,000 participants, who will be given the vaccine or a placebo to determine if the vaccine protects them from infection.

It may take several months to get everyone in the trials vaccinated. Then we will monitor participants over the course of winter to assess whether those who received the vaccine are less likely to get infected. And if they do get infected, whether they are less likely to get sick than those who did not receive the vaccine. If we find that these vaccines reduce either of these parameters in a substantial way, then they would be brought forward to the Food and Drug Administration for approval for wider use.

Some of the vaccines will induce soreness at the injection site, just like other vaccines we use. The goal here is to show your immune system what the virus would look like if you got exposed, have the immune system react to that, and become better prepared to attack the virus if you become infected. These vaccines have passed safety requirements. I would encourage those who are interested to join the clinical trial. For more information about the vaccine study opportunities, please contact Marvin Hanashiro at mhanashiro@health.ucsd.edu or 619-543-3740.

Q. How does the SARS-CoV-2 virus spread?

A. We've been learning a lot about the virus over the course of the last six months, both from the perspective of laboratory studies and looking at how outbreaks occur. This virus spreads through a combination of droplets, aerosols and fomites.

• Droplets: big bundles of liquid that are expelled when we talk, cough, yell or sing. These are heavy and fall to the ground.
• Aerosols: microscopic droplets of fluid that can spread over a longer period of time and can linger in the air after you have left a room. These are the drivers of the epidemic.
• Fomites: when the virus is deposited on surfaces like a desktop or doorknob, which could potentially infect you if touched. However, we are learning that this is not one of the major routes of transmission.

The route of respiratory spread has been oversimplified. A declaration was made without any research being done that this virus only spreads through droplets. If you stand very close to somebody, you’re getting exposed to both droplets and aerosols. You can get infected by both. If you are sitting far away, you can still get infected by aerosols, and that’s why you should wear a mask. I am a very strong proponent of masks whether you are within six feet of someone or not.

Q. How do masks play a key role in slowing virus transmission?

A. Masks decrease infection rate in both directions. They prevent you from spreading the virus to other people—particularly important if you are asymptomatic. There is emerging evidence that the higher the dose of the virus you get when you’re exposed, the more likely you are to have severe disease. Masks protect you from getting sick and substantially decrease the amount of exposure you may have.

One of the things that has been a major misconception is the message that if you can't physically distance, you should wear a mask. If you're in a room with someone, you should be wearing a mask because the aerosols will spread beyond six feet and will be in the air throughout the room. This can also apply to family members who may be visiting. For example, a grandparent visiting their grandchildren who are in school should wear a mask. And if you’re in a crowd outdoors, you should also wear a mask there. The message is simple: wear a mask—that’s the best way to protect ourselves and others.

Q. Why is it that younger people are less likely to show symptoms?

A. We know that very young people, under the age of six, seem to have fewer receptors for the virus in their respiratory tree. They may be less likely to get infected, and if they do, less likely to grow the virus effectively. Once you get above the age of 10, you're just as likely to get infected and shed the virus. However, someone who is 20 is less likely to get sick or show symptoms than someone who is 40. And someone who is 40 is less likely to get sick or show symptoms than someone who is 60.

What we know is that as you become older, your immune response is less vigorous. With coronaviruses, in particular, this immunological decline seems to be exaggerated. Younger people with a strong immune response can get control of the virus early and show less symptoms. Older people may have to struggle a bit harder to mount an immune response that can control the virus, and this can cause a fever and potentially lead to pulmonary disease that may be due to an overshoot of this more tardy immune response.

It is important to state though that people between the ages of 20 and 40 are the drivers of this epidemic. Young people are getting infected and have died. This does not happen as often as someone who is over 80 years old, but the number of young people in our intensive care units has increased substantially since Memorial Day. Until we get this virus under control, we are going to have to decrease socializing. Otherwise, we are extending the length and severity of this epidemic.

Q. Can you describe how testing samples are processed at UC San Diego?

A. UC San Diego’s testing capacity has been evolving steadily since early April. There are two laboratories that have been ramping up sample processing.

• The Center for Advanced Laboratory Medicine (CALM) at UC San Diego Health is now able to deliver between 1,000-2,000 tests a day, primarily focused on clinical care. By fall quarter, they are on target for 6,000 samples a day.
• A new lab, Expedited Covid IdenTification Environment (EXCITE), is also ramping up to provide 6,000 tests per day by the fall. EXCITE is co-led by UC San Diego faculty members Rob Knight, Ph.D., founding director of the Center for Microbiome Innovation and professor of Pediatrics and Computer Science & Engineering, Gene Yeo, Ph.D., MBA, professor of Cellular and Molecular Medicine and co-director of the Bioinformatics and Systems Biology Graduate Program, and Louise Laurent, M.D., Ph.D., professor and vice-chair for translational research in Obstetrics, Gynecology and Reproductive Sciences.

These two labs allow us to have plenty of capacity at UC San Diego Health and begin to extend our ability to test people who are asymptomatic. By detecting who is infected, not just waiting for people to arrive who are ill, we can get out in front of the virus and prevent it from being transmitted to others. I hope UC San Diego can serve as a broad resource to all local schools, businesses and the community in general, to get back to business.

Have more questions? We invite the campus community to submit your inquiries online. A new Q&A with a Return to Learn expert will be published each Thursday in This Week @ UC San Diego for the next several weeks.