More people are receiving multiple negative COVID tests before eventually testing positive after exposure or symptoms with new circulating subvariants, Chicago’s top doctor said Thursday.
The reason for this change could be due to vaccinations.
“We think that’s partly because, especially if people are fully vaccinated and/or have had COVID before, they’re not always…they don’t get as sick,” said the Dr. says Allison Arwady. “They’re like not learning as much from an immune response and sometimes it can take a little longer for that test to come back positive. The good news is, usually…if the home test is negative, you’re not very likely to have enough virus to spread, to be contagious.”
Arwady noted that PCR tests are more sensitive than home tests, but said anyone with symptoms or who may have been exposed should mask up for the full 10 days, regardless of their test results.
According to the Centers for Disease Control and Prevention, “positive self-test results are highly reliable.”
Negative results, however, may not rule out infection, especially in people with symptoms of COVID-19, the CDC says.
The CDC recommends those who test negative test again 24 to 48 hours after their first test.
“Consider repeating the test 24 to 48 hours later,” the guide says. “Multiple negative tests increase confidence that you are not infected with the virus that causes COVID-19.”
Although PCR tests may be more effective at detecting the virus, some people who contract COVID-19 may have detectable virus for up to three months, although this does not mean they are contagious.
As for testing, PCR tests are more likely to continue to detect the virus after infection.
“The PCR test can stay positive for a long time,” Arwady said in March.
“These PCR tests are very sensitive,” she added. “They keep picking up dead virus in your nose for sometimes weeks, but you can’t grow that virus in the lab. You can’t spread it, but it can test positive.”
The CDC notes that the tests “are best used early in illness to diagnose COVID-19 and are not cleared by the U.S. Food and Drug Administration to assess duration of infectiousness.”
For those isolating due to COVID infection, there is no testing requirement to end isolation, however, the CDC recommends using a rapid antigen test for those choosing to take one.
The CDC says those with symptoms should test immediately. Those who have been exposed but do not show symptoms should be tested five days after exposure.
According to previous CDC guidelines, symptoms of COVID can appear anywhere from two to 14 days after a person has been exposed to the virus.
Anyone with symptoms should get tested for COVID-19.
Some people may never experience symptoms, although they can still spread the virus.
A person is also considered contagious before symptoms appear.
Arwady noted that milder cases of the virus can make determining symptoms more difficult.
“We see a lot of COVIDs that are often quite mild,” she said, though she added that some early studies may show more intense disease, especially with the new BA.4 and BA subvariants. .5.
“With BA4 and BA.5 in particular, there have been animal studies that have shown, for example, a little more what we call pathogenic, a little more problematic like in some animal lungs and stuff where testing were done – mice, etc.,” Arwady said. “And potentially BA.4, BA.5 could be a bit more intense, but overall I think, you know, if you’re vaxxed and boosted, I’m just saying thank goodness you’re vaxxed and boosted if you’re having, you know, significant symptoms, because that’s a sign that you could have been even sicker.”
According to the CDC, these are the symptoms of a COVID infection:
- Fever or chills
- Shortness of breath or difficulty breathing
- Muscle or body pain
- New loss of taste or smell
- Sore throat
- Congestion or runny nose
- Nausea or vomiting
Arwady said that while the symptoms don’t seem to be changing, there’s a misconception she wanted to dispel.
“We continue…for some reason people have told me they don’t think you lose taste and smell with omicron. You can also lose taste with omicron. We’ve seen a lot of people having this temporary loss of taste and smell, which continues to be the most specific, like someone has lost taste or smell, I’m like, ‘That’s COVID.'”