story by Homma Rafi
Director of Communications, School of Public Health
On February 4, 2020, Georgia State University published its first news release on the coronavirus, back when it was known as 2019-nCoV and before the World Health Organization declared the pandemic. The story featured Dr. Gerardo Chowell, a professor of epidemiology in the School of Public Health, who has used his expertise in mathematical infectious disease modeling to predict the impact of SARS-CoV-2 — and now, its variants — since the onset of its global spread. Here, he reflects on what experts have learned about the virus in the past year and what to expect for the future.
It’s been more than a year since we interviewed you about the coronavirus, and since then you’ve been forecasting the trajectory of the pandemic on a national and global scale. What have you learned?
When you have a new virus, there are many uncertain variables that can complicate the development of accurate infectious disease modeling. During the first few weeks of tracking this pandemic, we noticed fluctuations in the number of tests conducted and positive cases reported over the weekends were lower in comparison to weekdays. There were also significant delays in the reporting of positive cases. These variables caused noise in the data.
Making sense of the noise became an important training component for the public health students taking my infectious disease modeling course. Working with biostatistics professor Dr. Ruiyan Luo and other collaborators, we’re continuing to make significant adjustments and improvements in the methodological toolkit, which in turn has improved the accuracy of the weekly forecasts that predict the impact of the virus. Since April 2020, this work has been supported by a National Science Foundation RAPID grant, which was the first novel coronavirus research grant received by Georgia State University.
Overall, my team has learned that simpler models can be helpful in forecasting the trajectory of the impact of the pandemic in the short term. Long-term forecasting is further complicated given the changing situation with the new, highly transmissible variants.
What has surprised you the most about the virus?
I did not expect the fall and winter wave to be as severe as it has been. We did not take social distancing and protection measures as seriously as I was expecting on a personal level. Behavior is a very important factor in the transmission process of a virus and our ability to comply to safety measures is a strong component in transmission dynamics.
I’m not an evolutionary biologist, but I was also surprised by the quick evolutionary processes giving rise to new variants of significant concern. Viruses mutate all the time in order to find ways to persist in the population. SARS-CoV-2 has generated more than a hundred million infections, so the possibility of seeing epidemiologically relevant enhancements to the virus — or the new variants — had been in the back of my mind. Given that a substantial number of people are now being protected from severe infections either through natural immunity or vaccination, newly emerging variants could exhibit increasing transmission ability. We have a very smart virus here.
Will the vaccination campaign bring an end to this virus?
In short, it is clear that this virus here to stay. There are many questions surrounding how prior immunity is working against the new variants, and it is unlikely that the vaccine will bring a full stop to infections due to these variants.
In the short term, the vaccination campaign will mitigate the severity of disease and help us fight COVID-19 by reducing severe infections that lead to hospitalization or death. And combined with continued mask-wearing, good hand hygiene and social distancing, it may eventually bring an end to the pandemic by substantially reducing the virus’s prevalence.
It is likely that a COVID-19 booster shot or seasonal coronavirus vaccine will be necessary every fall, similar to a seasonal flu vaccine.
Some countries do not have access to the vaccine to protect their populations and some countries have already vaccinated 80 percent of their populations. How does this disparity affect our ability to fight the pandemic?
The impact of the vaccine rollout has been quite heterogeneous. There is a limited number of countries who have access to the vaccine, and there are United Nations Council reports that some wealthier countries are hoarding the vaccine in quantities to cover several times their population size while other countries have not been able to vaccinate their healthcare workers, let alone a single citizen. There is great concern that those countries are at risk for seeing a severe wave of infections during fall and winter 2021.
Our job now is to mitigate the impact on mortality by developing stronger surveillance systems to detect new variants in a timely way, so rapid development of vaccine boosters are developed and rolled out on a seasonal basis. We are all connected, and we all need each other to ensure stability and economic growth. We need a coordinated vaccination campaign effort on a global scale. If several countries do not have access to this vaccine and are not protected from the virus, then that causes severe economic impact within that country and that cascades around the globe.
Hopefully, by the end of 2021 significant improvements in vaccine production and distribution can happen to provide access to the countries who have not been able to procure it yet.
Nobody is immune to the effects of this virus. Scientists, researchers, the public — everyone is burned out. What gives you hope as we reflect on the one-year anniversary of the pandemic?
It gives me hope each time we can get the vaccine in the arms of people to help reduce the transmission of COVID-19, which will dramatically reduce the number of hospitalizations and deaths caused by the disease. We should be hopeful that we have the scientific capability to continue to develop the vaccine to boost its effectiveness and combat the variants, if needed.
This year is still uncertain since the global vaccine rollout has been choppy, but within two to three years, we should see important changes in the mortality impact caused by this virus. Though it is here to stay, my hope is that the virus will reach an endemic stage and its infection fatality rate in a fully immunized population will become more in line with that of other endemic respiratory viruses such as the flu. Overall, we need to be patient and contribute at the individual level by following social distancing requirements and getting the vaccine when it’s made available to us.
Dr. Chowell's weekly coronavirus forecasts are publicly available at the following School of Public Health website: publichealth.gsu.edu/coronavirus