(WHTM) — As we approach the third year with COVID-19 circulating in the U.S., questions about the virus still abound. It might feel like everyone you know is catching the coronavirus lately, so we asked experts about reinfections, tests, and when you can get together with people again after catching COVID.

Q: How long after recovering from COVID-19 could someone catch it again?

“The original recommendation from CDC was that once you had a COVID infection, for the next 90 days — the next three months — you were very unlikely to get COVID again. That’s been the case pretty much all along and I think it still holds, although keep in mind that with omicron, omicron can infect people that had COVID, say, back in the fall. So if you had the delta variant back in September, that only protects you to about 20% against omicron.

“One of the hallmarks of omicron is this concept of immune evasion; it can evade the immunity that’s generated by a prior natural infection, and it also to some extent can evade the immunity created by immunization.”

-Dr. Joseph Kontra, chief of infectious diseases, Penn Medicine Lancaster General Health

“We are assuming that you are fully immune for at least 90 days… There is a lot of evidence that it probably goes up to about six months, but that’s a probably. And then likely, immunity from natural COVID infection probably declines just like immunity from the vaccine declines with time.

“Part of the issue is that in a virus that just appeared a little less than two years ago, we obviously can’t say you’re immune for more than two years because it simply hasn’t existed long enough. So there’s a lot of what I would frankly admit is guesswork, but what I will tell you we’re seeing is with omicron, we’re seeing a lot of breakthrough infections in vaccinated individuals, fewer breakthrough infections in people who are vaccinated and have had a booster, and we’re also beginning to see, though at a lesser rate, people who are reinfected with COVID.

“The good news is that if you are vaccinated, you are much, much less likely to get very sick.”

-Dr. John Goldman, infectious disease specialist, UPMC

“Reinfection from SARS CoV-2 does occur. This is why CDC has always recommended that patients with a history of COVID-19 get vaccinated after clinical recovery. Natural immunity from COVID-19 is variable from patient to patient. Some medical experts have shown that asymptomatic/mild infections do not generate the robust immune response of those who experienced a severe infection. It is therefore difficult to predict an individual’s duration of natural immunity, which some studies mention may last 1-6 months.”

-Dr. Eugene Curley, infectious disease physician, WellSpan Health

Q: How common are reinfections? Are there differences between vaccinated and unvaccinated individuals?

“What we’re seeing is reinfections are common, they occur with omicron, although we haven’t seen a lot of people get really sick or end up in the hospital with reinfections. What we also assume is that as antibodies gradually decline from natural infection, we’ll probably see more reinfections, and as the virus evolves, as it comes to new variants, we’ll probably see reinfections.

“My impression is that we have more breakthrough infections in people who have their first two shots but not the booster. The one thing that’s always extremely important — people sometimes go, ‘Well if I’m going to get reinfected, if I’m going to have a breakthrough infection, why should I get vaccinated?’ The real issue is, if you have a breakthrough infection, it’s likely to be very mild. We have seen breakthrough infections, but they tend to be something that resembles a minor cold, a slight increase in allergies. We have people who get sicker, but they rarely end up in the hospital.”

-Dr. John Goldman, infectious disease specialist, UPMC

“We are still learning how variants play a role in reinfection. Vaccinated individuals are not spared from reinfection. However, the vaccines do protect from severe disease, hospitalization, and death in immunocompetent persons who are boosted.”

-Dr. Eugene Curley, infectious disease physician, WellSpan Health

“In general, you are probably five to 10 times more likely to become infected if you are unvaccinated, and you are probably 15-20 times more likely to die from COVID if you end up being hospitalized.

“If you are vaccinated, even though you may get infected…it is likely to be mild, it’s likely to last a shorter amount of time, you’re less likely to transmit it to someone else and more quick to recover from it.”

-Dr. Joseph Kontra, chief of infectious diseases, Penn Medicine Lancaster General Health

Q: If you are unvaccinated and catch COVID-19, how long should you wait to get vaccinated?

“What I advise people is to wait 90 days because we know that you’re immune for 90 days, and if you have pre-existing immunity, you may get more side effects from the vaccine. So I typically recommend 90 days. You can make a case for waiting, I think you’re safe to wait up to six months, but because we don’t understand a lot about when you truly lose immunity, I would do it after 90 days.

“The one thing would be if you’re immune-suppressed for whatever reason, I would do it right away because people who are immune-suppressed probably have less long-acting antibodies.”

-Dr. John Goldman, infectious disease specialist, UPMC

“According to CDC guidelines, you can wait for those 90 days, but in point of fact, people often tend to do it much sooner, and I would say as soon as you’re not feeling ill anymore, and as long as you’re outside of your isolation period — seven, 10, or 21 days depending on your immune status — once you’re beyond that and you’re feeling well, you can get the vaccine, and there’s no harm in getting it sooner than 90 days.”

-Dr. Joseph Kontra, chief of infectious diseases, Penn Medicine Lancaster General Health

Q: How reliable are COVID-19 test results? Can you trust a negative test result to mean you are no longer infected?

“That depends a little bit on what type of test you’re taking and when you’re testing. What we have found is that antigen tests pick up about 2/3 of the positive cases compared to PCR. So if you’re taking an antigen test, you have about a 1/3 chance of missing a positive compared to a PCR.

“We have seen, especially in patients who are vaccinated and have household contacts, that their first test is often negative and their second test is positive. So for example at UPMC, if you have had a household contact and you have symptoms, in order to come back to work you need to have a first test and then a second test three to five days later, both have to be negative.”

-Dr. John Goldman, infectious disease specialist, UPMC

“Antigen tests (most home tests) are not as sensitive as PCR tests. Antigen tests are therefore more prone to false-negative testing. In certain situations (i.e. exposed/symptomatic person), a repeat test should be performed if the antigen test is negative. The antigen tests are good tools if you understand their limitations and the clinical context of the particular case. I recommend that patients talk with their healthcare provider regarding the results of home testing to direct need for retesting, isolation, return to work/school, and treatment.”

-Dr. Eugene Curley, infectious disease physician, WellSpan Health

“It kind of depends on the circumstance. Say you’re in a household where someone has COVID and you start to be ill, you start to get a cough and fever, the likelihood that you have COVID is very high. So if you get a negative test, I would consider that an unreliable result, especially if you’re using one of the home kits. So in that situation, you should go and get a PCR test at a medical facility.

“The home tests are able to pick up infection after a few days of your being infected. The PCR test, on the other hand, picks it up right away. So the home antigen test will pick you up if you do it repeatedly, and remember that the kits come typically with two swabs; you’re not supposed to use it on two people, you’re supposed to use it on yourself today and about 36 hours later because those two tests together will more likely pick up your infection if you have it.”

-Dr. Joseph Kontra, chief of infectious diseases, Penn Medicine Lancaster General Health

Q: How long after contracting COVID-19 can you safely get together with other people again?

“If (you or) your friend had severe disease, meaning they ended up in the hospital or ended up needing oxygen, you’re advised to wait 20 days* before they’re not infectious, before you’d be safe to hang out with them. If you had mild disease [and] provided you’re getting better, provided you have no fever, without a test, 10 days, and with a test, you can test on day five, and if the antigen test or the PCR is negative, you’re safe, you’re considered to be non-infectious.

“The issue is, one, the PCR often stays positive for 30 days, and I’ve seen it stay positive for months. And two…for example, if I had to hang out with an elderly parent or someone who is at risk, I wouldn’t do it before day 10 without a negative antigen test, and I probably would wait till day 10 if the other person, if they got COVID, were at risk of getting very sick.

“So severe disease — 20 days. Mild disease, no testing — 10 days. Mild disease with a negative antigen test — at day five, you can go back to work.”

*This is the number of days after developing symptoms

-Dr. John Goldman, infectious disease specialist, UPMC

“I wouldn’t trust tests that are done on consecutive days if one’s positive and one’s negative. But say someone’s infected and they’re getting better at five days, and they have another home antigen test and that’s negative, that person can then go and be around others with very little risk of transmission.”

-Dr. Joseph Kontra, chief of infectious diseases, Penn Medicine Lancaster General Health