Among the many reports of positive COVID tests in Olympic athletes, one of the most confusing was in the golfer John Rahm. He had been found to be infected with COVID on June 5th and forced to withdraw from the Memorial Golf Tournament in Ohio. Despite this, two weeks later he tested negative for the virus and was allowed to compete in the U.S. Open at Torrey Pines. He won that tournament and subsequently has played in several events including the British Open the weekend of July 17th. So it was surprising that in pre-Olympic screening this week Rahm was found to have evidence of the SARS-CoV-2 virus in his nose and forced to withdraw from the competition.
One has to ask how can someone who was infected with COVID-19 in early June still harbor the virus in late July?
Rahm’s unusual situation demonstrates a unique scenario that can result from ongoing random COVID-19 screening and variations in COVID restrictions. Rahm was COVID-19 infected and subsequently vaccinated, but still showed evidence of virus. Despite this (and feeling entirely healthy) he was tested by protocol before his departure to Japan. He was then COVID screened for the Olympics as part of the Japanese government’s aggressive approach to controlling the pandemic at the games. Because he is fully vaccinated against COVID-19, Rahm is no longer even screened for virus for PGA tournaments. If this were up to the IOC or the PGA, he was good to go. But the Japanese government is not allowing anyone into the country with a positive test, regardless of their immune status.
What Rahm’s situation demonstrates is that even people who develop immunity can carry small amounts of virus for months after the initial infection. Most experts do not believe people in Rahm’s situation can infect anyone else. That is because the amount of virus that can be detected with PCR tests is very small, as the PCR amplifies the virus genetic material 30 million times or more. Therefore, while Rahm had some amount of virus in his nose, it was not making him ill and was likely such a small amount, he would not be able to infect anyone else.
This situation is different from “breakthrough” infections in vaccinated individuals who were not previously infected. Roughly 5-10% of fully vaccinated individuals can be found to have SARS-CoV-2 virus in their nose, an indication of an infection. This means they were infected despite full virus immunity, but fortunately most of these folks are not ill. This is reinforced by the finding that currently in the U.S. 96% of hospitalizations and 99% of deaths from COVID are in unvaccinated individuals. Vaccinated individuals also seem to be less likely to have “long-haul” COVID or prolonged shedding of virus. Therefore, true “breakthrough” infections tend to be very limited in their duration and impact.
Given this knowledge, John Rahm would likely be playing in the Olympics if he had been vaccinated before he was infected.