The Centers for Disease Control and Prevention (CDC) of the United States changed its guidance for how long persons should isolate after contracting COVID-19 infection in December 2021. The agency reduced the duration of isolation from ten to five days, followed by five days of mask-wearing for individuals who were no longer symptomatic after that.
The decision was made during the height of the omicron variant’s popularity and the resulting scarcity of personnel in hospitals, schools, and enterprises. Some opponents speculated that the decision was more pragmatic than scientific in nature and that it was made to enable employees, particularly those in the healthcare industry and other vital people, to return to their jobs more quickly.
As a consequence, I felt it would be beneficial to evaluate the research that supports the most recent guidelines in order to assist individuals in considering best practices.
In my professional life, I work as an infectious disease expert at the University of Virginia. As a nurse practitioner, I care for patients who have been admitted to the hospital with COVID-19 and perform research on how the immune system reacts to infection.
The CDC’s current strategy
First, let’s distinguish between the phrases “isolation” and “quarantine.” Isolation is a kind of quarantine, while quarantine is a type of quarantine. Since the outbreak, individuals have frequently used the terms interchangeably to describe the situation. However, whereas isolation is intended to separate infected persons from those who are not, quarantine is intended to separate those who have been exposed to COVID-19 but have not yet tested positive or are not exhibiting symptoms.
To be clear: If you are infected with COVID-19, the current recommendations from the Centers for Disease Control and Prevention have reduced your isolation time by half, to five days from the beginning of symptoms, or the first positive test if you are not experiencing symptoms. After five days, as long as you are improving, the Centers for Disease Control and Prevention (CDC) recommends that you no longer isolate but should continue to wear a mask among others for another five days.
If you have been exposed to COVID-19 and have not yet had your booster vaccine, the Centers for Disease Control and Prevention (CDC) advises that you quarantine for five days after exposure. You should be tested between days five and seven, and if the test comes back negative, you may be released from quarantine. If you are within 6 feet of an infected individual for 15 minutes or longer during the course of a 24-hour period, you should consider yourself exposed. Furthermore, the Centers for Disease Control and Prevention (CDC) states that if you have been vaccinated and boosted, you do not need to quarantine after being exposed to COVID-19 – albeit you should get tested five days later and ask for at least 10 days following exposure.
Regardless of your vaccination status, the Centers for Disease Control and Prevention (CDC) advises that you undergo a fast antigen test or a polymerase chain reaction (PCR) test five to seven days after exposure to ensure that you did not get COVID-19 before exiting quarantine.
New studies support these CDC recommendations
What is the basis for these suggestions in terms of evidence? Although researchers are still learning about omicron – as the Centers for Disease Control and Prevention (CDC) notes, “the knowledge is changing” – some studies show that its symptoms manifest themselves more quickly after exposure as compared to its delta version. This comprises the findings of four short studies conducted in Nebraska, Norway, Japan, and the National Basketball Association of the United States of America (NBA).
It was discovered in Nebraska that a family of six members had all been exposed to the omicron version of SARS-CoV-2, the virus that causes COVID-19. Affected individuals began to show signs of infection after one to three days of exposure, which is one to two days quicker than the delta variation. This research lends credibility to the suggestions made by the CDC. In Norway, roughly 100 people were exposed to omicron during a Christmas party; the majority of them contracted COVID-19, with symptoms developing and infections being discovered within two to five days of exposure, which was again far sooner than would have been predicted for delta infection.
Research conducted in Japan on 21 patients who had been infected with omicron discovered that the quantity of virus present was at its maximum of three to six days following the diagnosis or commencement of symptoms. An investigation of the NBA COVID-19 monitoring system revealed that a person with omicron was generally no longer contagious by the fifth day after contracting the virus.
Taken together, these investigations imply that by day five, the vast majority of persons who were infected with the omicron form or who had an exposure had no longer been able to spread the virus.
These four studies demonstrate the rationale for the Centers for Disease Control and Prevention’s decision to reduce its isolation and quarantine guidelines to five days. As a result, the great majority of individuals are unlikely to transmit the virus at that stage after infection, therefore it seems reasonable that they may return to their usual activities.
The follow-up test is critical if you were exposed and in quarantine
The caveat, however, is that transmission rates of COVID-19 may only be decreased by half if a fast antigen or PCR test is not performed five to seven days after the initiation of quarantine.
As a result, both the Centers for Disease Control and Prevention and the World Health Organization suggest that follow-up tests be performed within five to seven days following the commencement of quarantine.
According to mathematical models, either quick antigen or PCR testing allows for a reduction in quarantine time without affecting public health and safety.
Also, as of early March 2022, approximately 57 percent of Americans who are completely vaccinated had not taken the booster vaccine. So, it is estimated that tens of millions of Americans have not yet taken this additional step to better protect themselves from the virus.