(NEXSTAR) — With omicron cases rocketing upward in what Dr. Anthony Fauci has called a “vertical spike,” many may be considering a COVID-19 test after meeting with friends and relatives during the holidays.
For those who know they have been exposed to someone who tested positive for the virus, or are just feeling a bit ill, it’s unfortunately not quite as straightforward a process as it could be.
Dr. Peter Chin-Hong, an infectious disease expert at the University of California at San Francisco School of Medicine, told Nexstar that it’s better to wait 3-5 days after exposure before going for a test. That rule of thumb applies to both polymerase chain reaction (PCR) tests and at-home rapid tests.
A PCR test will take longer because a lab has to process the sample, but it is more sensitive when it comes to detection of early disease. Genetic tests, which use nasal swabs or saliva, can register bits of the coronavirus’ genetic material – as long as there is a good sample to work from.
Rapid antigen tests, such as the Abbott Labs product that has been flying off drugstore shelves across the country, give results in minutes but aren’t as accurate as a genetic test. The widespread use of at-home tests also has experts worried that the results – which are often not reported to health officials – may skew national tracking data.
If you’re planning on getting tested but are still waiting for the optimal window, Dr. Chin-Hong suggests wearing a mask to avoid inadvertently infecting others. CDC guidelines also state you should self-quarantine after an exposure if you haven’t gotten a booster shot (and are eligible) or aren’t fully vaccinated.
New recommendations for isolation, quarantine
The Centers for Disease Control and Prevention on Tuesday explained the scientific rationale for shortening its COVID-19 isolation and quarantine recommendations, and clarified that the guidance applies to kids as well as adults.
The CDC also maintained that, for people who catch COVID-19, testing is not required to emerge from five days of isolation — despite hints from other federal officials that the agency was reconsidering that.
The agency announced the changes last week, halving the isolation time for Americans who catch the coronavirus and have no symptoms or only brief illnesses. Isolation should only end if a person has been fever-free for at least 24 hours without the use of fever-reducing medications and if other symptoms are resolving, the CDC added.
It similarly shortened the time that close contacts need to quarantine, from 10 days to five.
CDC officials previously said the changes were in keeping with evidence that people with the coronavirus are most infectious in the two days before and three days after symptoms develop.
Some experts have questioned how the new recommendations were crafted and why they were changed amid a spike in cases driven largely by the highly contagious omicron variant. Some also expressed dismay that the guidelines allowed people to leave isolation without getting tested to see if they were still infectious.
The Associated Press contributed to this report.