Once you’ve had COVID-19, you’re safe from getting it again, right?
A northern Nevada man learned the hard way earlier this year that getting re-infected with COVID-19 soon after surviving it just might be possible. After testing positive in April, the man subsequently tested negative multiple times until becoming ill just 48 days later and testing positive again in June.
To figure out what was going on, scientists from the Nevada State Public Health Laboratory at the University of Nevada, Reno, along with UNLV researcher Richard Tillett with the Nevada Institute of Personalized Medicine, looked deeper into the genetic blueprint of the man’s virus samples and found differences between the two cases.
In other words, he was infected twice.
“Thankfully, reinfection looks to be pretty uncommon,” says Tillett. “And I hope that it remains that way.”
Still, the work conducted by Tillett and colleagues uncovered the first confirmed case of a person reinfected with the virus in North America. Their research was published in the prestigious medical journal The Lancet Infectious Diseases in October.
The scientific community – in Nevada and beyond – has rallied together like never before to uncover the many mysteries of COVID-19.
Tillett, a biostatistician, joined UNLV in August after working with the Nevada Center for Bioinformatics in Reno. He studies the genome – or building blocks – of disease, and his work with the Nevada Institute of Personalized Medicine is now squarely focused on finding ways to conquer COVID-19.
We spoke with Tillett to learn more about the likelihood of COVID-19 reinfection, the team’s landmark study, what’s next, and his advice for what we can all do to keep ourselves and our loved ones safe.
You were on a research team that made headlines in October when it documented a Northern Nevada man who contracted COVID-19 twice in less than two months. What was your role in the research?
My role in this study was to analyze the virus genomes collected from this patient from his earlier and later positive tests, compare the genomes to one another and to genomes in circulation, and finally, either find evidence that the two viruses differed or rule it out.
How was the research team notified of a possible reinfection case?
We identified the man, a Washoe County resident, as a part of our effort to survey SARS-CoV-2 genomes across Nevada. With both public health labs in the state providing samples, corresponding author Dr. Mark Pandori, director of the Nevada State Public Health Lab with the University of Nevada, Reno, was able to identify the man.
Can you break down for us how we know the man was infected two separate times, instead of suffering from one lingering case?
We started with a basic set of facts in the testing history. We knew that the patient had tested positive via the PCR test, which is used to diagnose active infection. He had symptoms, then improved. He subsequently had two negative tests, indicating his infection was over. Then six or seven weeks after his first positive test, he felt sick again, got tested again, and was again positive.
Now, PCR test results like these are only suggestive of re-infection. In order to confirm reinfection, we needed to sequence the viral genomes from both positive tests. When we obtained those genome sequences, we found six differences between the virus in the samples, by which we were able to rule out alternative scenarios such as it being one long infection.
What was your first thought when the work came back verifying that the man had, in fact, contracted COVID-19 a second time?
Honestly, I felt fright. We had to be sure we were right if we were going to claim proof that the possibility of reinfection was more than possible, but had actually happened for this person.
Do you think this a rare case, or is this more common than we might think?
Currently, reinfection looks to be pretty uncommon. And I hope that it remains that way. Though we don't yet know how long an average person may have lasting immunity to SARS-CoV-2, less than a year into this pandemic, it currently looks like reinfection is not the norm.
Given these results, what’s your advice for people reading this who may have thought COVID-19 was a “one and done” virus?
My advice is to stay vigilant. Wear masks. Social distance. Avoid gatherings. Wash your hands. And if you feel like you maybe haven't been doing a great job at enacting these suggestions, this is too important to beat yourself up over. Remember that it’s not too late to start or restart lowering your exposure risk.
Why is it important that researchers throughout Nevada and the nation continue to work together to tackle the COVID-19 pandemic?
The research community here in Nevada, the U.S., and globe are doing great work together in response to the pandemic and have embraced collaboration and knowledge-sharing to help tackle this threat. Our hope is that continued study will help us understand this virus, track it, monitor unfolding outbreaks, and keep guard in the future, even after vaccines become widely available.
What’s next? Given the stunning results of the reinfection study, what other areas related to COVID-19 are you and colleagues investigating now?
At the Nevada Institute of Personalized Medicine, my colleagues – including Professor Edwin Oh – and I are continuing to track and study COVID-19 genomes from Nevada patient samples.
We’ve begun a major effort to detect SARS-CoV-2 in wastewater, and once detected, identify the mixture of mutations found in the viruses in that wastewater. This work will give us a tremendous amount of new information on the burden and spread of this virus in the community complementary to and beyond patient samples.