Q&A: Stanford epidemiologists on breakthrough COVID-19 cases, pandemic forecasts

Aug. 6, 2021, 1:08 p.m.

As more people in America are vaccinated for COVID-19, a small number of breakthrough cases — infections among fully vaccinated people — have appeared. While over 90% of the Stanford community on campus has been vaccinated, recent weeks have seen several breakthrough cases among students living on campus. The Daily sat down individually with two epidemiologists to discuss their advice for students, research of the pandemic and forecasts of the future. 

Steven Goodman is the associate dean of clinical and translational research and a professor of epidemiology and population health and of medicine. During the COVID-19 pandemic, he served as senior author in research into “long haul” symptoms. John Ioannidis, who serves as co-director of the Meta-Research Innovation Center at Stanford (METRICS), is a professor of epidemiology and population health, of medicine and of statistics and biomedical data science.

The Stanford Daily (TSD): Stanford recently experienced at least seven breakthrough cases on campus. How can students best stay safe on the campus and in areas where they might come into contact with many people? 

Steven Goodman (SG): If they’re vaccinated and they got COVID, they still may be pretty safe in the sense that breakthrough infections rarely, even in older people, make people very sick. There are a lot of things we don’t know, that we’re still learning about the virus. But in terms of staying uninfected, people have to use the same common-sense practices that we did when we didn’t have vaccines. When you’re inside, in relatively close contact, you should absolutely wear a mask. Outside I still don’t think there’s much of a risk, even less so for vaccinated folks. 

John Ioannidis (JI): We know that the vaccines that have been used are very effective, in the range of 95%. However, nothing is 100% in reality. So, this means that one still has to be cautious when there is an active epidemic wave. With the current wave, it’s not possible to tell how it will look even a week down the road. Whatever we have been saying about trying to protect yourself and others during the pandemic still makes sense. It’s not something to panic about, but we just need to hold onto that perspective.

TSD: Is what happened at Stanford representative of a national trend? 

JI: The numbers are small, but I believe that it’s very likely that we will be seeing this situation on many campuses. In a way, the number of cases that you document depends also on how much testing you do. So, on a campus that does more testing, you may get more cases without that necessarily meaning that the situation is out of control.

TSD: What is your forecast for the future of the pandemic given the breakthrough cases and recent variants? 

SG: Let’s not forget that there’s still a raging epidemic going on around the world. We feel very protected here in our bubble of highly vaccinated areas, but there are many areas in the United States where there are many unvaccinated people. The rates [of COVID] are still rising quite quickly, in both the vaccinated and unvaccinated. Now, that of the vaccinated is much much lower, but the unvaccinated are continuing to provide fuel to that fire. If we can lower the number of unvaccinated, then the cases in the vaccinated will be even lower. So in our country, we have to break through some of this resistance to vaccines. 

TSD: Stanford recently ended mandatory COVID-19 surveillance testing within the on-campus population. Would you say that reinstating health measures such as this would be necessary amidst the breakthrough cases? 

SG: I don’t think so right now. As with everything in this epidemic, things change by the minute, by the day. So obviously Stanford and Santa Clara County and neighboring counties are monitoring cases very, very closely. I think before we make big changes in how we operate we need to understand patterns of the breakthrough cases. Breakthrough cases are not a reason for panic; they’re expected. If we start getting many, many more and any of them start getting very, very sick — that’s the key — or an appreciable number start having long COVID, then we may want to adjust practices. 

TSD: What is the most important part of dealing with COVID-19 now as we’re seeing rises in breakthrough and variant cases? 

JI: The most difficult aspect is to try to deal with this crisis in a calm way and maintain some social cohesiveness, some sense of social responsibility and community. I do worry that this pandemic has really created more inequality. Many of the people who were hard hit were disadvantaged people. The longer the pandemic lasts, the higher the chances that these gaps will widen. People are sick, people are afraid, and they panic. So I would love to see everyone really caring for others and try to remain calm.

TSD: Are you interested in continuing your research toward the breakthrough and latest cases of COVID-19? 

SG: I think [long haul COVID] is the area, sadly, that’s going to affect the hundreds, potentially millions of people who’ve had COVID. Breakthrough cases are not my specific area of focus or expertise, but I’m interested in it as an epidemiologist, as a citizen, as a human being because we’re going to be living in a community, which is Stanford, where almost everybody is going to be immunized, breakthrough cases will be the only cases that we see or the dominant number. They might still be at risk for long COVID, and they also might represent infections with a new strain of the virus that we don’t quite understand yet and might evade the immune system a little better. 

JI: I think that it’s a unique opportunity to learn as quickly as possible. There’s still a lot of speculation, and it’s unavoidable because this was a new virus. We tried to extrapolate from what we knew from other coronaviruses, but nothing was like this coronavirus. SARS CoV-2 — especially now with the Delta variant — is spreading like crazy. We do have vaccines available, and hopefully we can keep up with modifying these vaccines if need be. It may end up being more like those other coronaviruses, which do exist and we live with them. I don’t want to say that it’s not a big deal, because even if a single person dies that’s a tragedy, but within the big picture, it’s something that is manageable.

This interview has been condensed and lightly edited for clarity.

Jack is a high school student in The Stanford Daily's Summer Journalism Workshop.

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