Ravens QB Lamar Jackson has tested positive for COVID twice. How common is reinfection?

Ravens fans may be feeling deja vu. On Wednesday, for the second time since November, star quarterback Lamar Jackson was sidelined due to a positive COVID-19 test.

This time it’s not on the eve of one of the team’s biggest games of the season, but at the beginning of summer training camp. And now, vaccines are widely available, making infections — and therefore reinfections — rarer.

Experts say Jackson is part of a small group of patients infected twice with the virus. It’s a group that could grow as new variants take hold, although vaccination can stem the tide.

Here are experts’ answers to common questions about coronavirus reinfection:

How common is reinfection with COVID-19?

So far, reinfection after an initial natural infection is rare, said Dr. Amesh Adalja, senior scholar at the Johns Hopkins Center for Health Security and an infectious disease physician.

But Adalja said reinfection with other coronaviruses — some of which manifest as common colds — is common after about a year. COVID-19 is probably no different, he said.

Maryland’s Department of Health doesn’t track occurrences of reinfection, spokesman Charles Gischlar said. The department plans to release data soon on how many vaccinated Marylanders are being diagnosed and hospitalized by the disease, and how many have died. Officials are hoping the low numbers will encourage the vaccine-hesitant to get their shots.

Jackson, for one, has declined to say whether he’s vaccinated, calling it a personal decision. But NFL protocol requires daily PCR testing for unvaccinated athletes, and Ravens coach John Harbaugh has said Jackson tested negative several days in a row before his positive result. Vaccinated athletes, who make up 90% of the Ravens roster, according to Harbaugh, are required to take a test only once every few weeks. All of the Ravens coaching staff is vaccinated against the disease, the team has said.

As COVID-19 continues to mutate, people may find themselves sick with different strains, Adalja said, a phenomenon that could continue until more people are vaccinated.

”Immunity to one may not be as robust as another,” he said.

The more contagious delta variant of the virus, which hadn’t been detected in November when Jackson was originally infected, is rapidly becoming the dominant strain in the United States. In Maryland, the delta variant was at least a third of cases tested by the Department of Health in June. And scientists say it’s only growing.

Florida, where Jackson typically trains during the offseason, has the second-worst case rate of any state in the nation, due in part to the rise of delta. Its rate — 58 per 100,000 according to The New York Times — is 11 times that of Maryland.

“If you’re in these areas that have high rates of transmission ... it makes it that much easier to get re-exposed,” said Christopher Thompson, a biologist and immunologist at Loyola University of Maryland.

The delta variant has been shown to have a shorter incubation period than previous iterations of the virus, around three to five days.

Are reinfected patients likely to suffer severe cases of the virus?

The first time Jackson contracted COVID-19, he said he felt flu-like symptoms, and lost his sense of taste and smell. He felt fatigued, and slept frequently, he told reporters.

“I wouldn’t wish that on anybody, though. It’s not good to have,” he said.

People with prior immunity are more protected from severe sickness and hospitalization, Adalja said, but can still contract COVID-19 and spread it.

The Centers for Disease Control reversed its guidance on mask-wearing Tuesday partially because of concerning new research, which indicated that fully vaccinated people can carry large loads of the delta virus in their noses and throats. That means they could be spreading the virus.

So-called breakthrough infections are unlikely to cause hospitalization or death. In June, all of the 100 people who died of COVID-19 in Maryland were unvaccinated. About 93% of patients hospitalized with the virus were unvaccinated.

But because reinfection cases are fairly rare, data about how they affect people is too, Thompson said.

“Without a good basis of data it’s hard to answer that question,” Thompson said.

Can people recently infected with COVID-19 get vaccinated?

Adalja said people should get fully vaccinated irrespective of a prior COVID infection. When vaccines were scarce, the CDC and others recommended those who had been infected with COVID-19 wait 90 days so those with no natural immunity could go first. That doesn’t apply anymore, he said.

There is also emerging data that just a single dose of the two-dose vaccines could be enough for people with prior infections.

The more people who get vaccinated against the disease, even with one shot, the fewer chances the virus will have to mutate, and potentially evolve a resistance to the established vaccines, Thompson said.

“People just believe they mutate on their own — but they don’t. They need to be in someone,” Thompson said.

As a result, Thompson said he finds it difficult to view vaccination as a solely personal decision, since it affects society as a whole.

The NFL has all but mandated that coaches get vaccinated, but Ravens officials have said they would leave the decision up to the players.

”If the goal is to have an NFL season as close to normal as possible, the path is to mandate the vaccine,” Adalja said. “Some teams are going to [be] playing in areas with widespread transmission. You’re going to inevitably get COVID.”