Random variation is an essential component of all living things. It drives diversity, and it is why there are so many different species. Viruses are no exception. Most viruses are experts at changing genomes to adapt to their environment. We now have evidence that the virus that causes Covid, SARS-CoV-2, not only changes, but changes in ways that are significant. This is the nineteenth part of a series of articles on how the virus changes and what that means for humanity. Read the rest: part onepart twopart threepart fourpart fivepart sixpart sevenpart eightpart ninepart ten,part elevenpart twelvepart thirteenpart fourteenpart fifteenpart sixteenpart seventeenpart eighteen, and part nineteen.

With variants spreading rapidly across the globe, we are entering a new stage of the pandemic and should proceed with caution to save lives. The U.K. B.1.1.7 and South African B.1.351 variants have demonstrated increased transmissibility and shown evidence of increased viral load, which is associated with increased disease severity and mortality. As we gather more data on the variants, we are learning that they act very differently from the original SARS-CoV-2 Wuhan strain, and we need to adjust public health protocols accordingly to prevent another rapid rise in cases. Two recent studies indicated that the infection incubation period for the variants is longer than the SARS-CoV-2 strain. Therefore we need to adjust the quarantine period to three weeks as China has done.           

The first study was conducted in Alachua County, Florida, when schools reopened in Fall 2020. Researchers investigated SARS-CoV-2 positivity rates among student contacts of positive cases on or after 9 days of quarantine. For 257 confirmed cases of SARS-CoV-2 infection, 2189 contacts were quarantined. 134 students (6.1%) were tested on day 3, and 839 (38.3%) were tested on days 9 to 14. Of the 134 student contacts tested on day 3, 14 (10.4%) were positive for SARS-CoV-2 infection. Of the 839 student contacts tested on days 9 to 14, 40 (4.8%) were positive for SARS-CoV-2 infection. 

Amid 799 student contacts of confirmed SARS-CoV-cases with a negative test result on days 9 to 14, one became symptomatic after returning to high school and had a positive test result on day 14 after their initial negative test result on day 9. After sequencing that virus, scientists found out that it was genetically different from the virus, which was initially isolated for the study.

I have discussed the second (not yet peer-reviewed) study from the Harvard University School of Public Health in detail for a previous Forbes column. The study analyzed the daily PCR tests of 65 NBA players, all infected with SARS-CoV2, seven of them infected with the U.K. B.1.1.7 variant. The mean duration of overall infection for the players infected with the variant was 13.3 days compared to the players infected with SARS-CoV2, who had a mean duration of infection of 8 days.  MORE FOR YOUNew SARS-CoV-2 Variant Discovered In Japan Nearly Identical To Dangerous Brazilian VariantThe U.S. Has Ordered Enough Of Pfizer’s Covid-19 Vaccine For 50 Million People—But That’s All2020 Election: Victories For Medical Marijuana, Tobacco Taxes And Other Healthcare Ballot Measures

Current CDC guidelines endorse a 14-day quarantine period as the gold standard or a seven-day quarantine period with a negative result on day five or later, or a 10-day quarantine without a negative test as an option to reduce quarantine. Both studies demonstrate the increased incubation period of the variants and the need to swiftly extend these quarantine guidelines. 

Due to the rapidly changing nature of the variants and a lack of comprehensive data, I am urging the CDC to err on the side of caution and extend the quarantine period to three weeks as China has done. I understand that a three-week quarantine is a far greater burden than 14 or 10 days. This is why I have repeatedly advocated for the federal government to assist those in isolation, financially, as well as with medical supplies and shelter if necessary. 

If we do not immediately implement this public health measure, well-meaning members of the public could be unknowingly infecting their community after only completing a 10 or 14-day quarantine. It is the duty of the CDC to keep the public informed of best practices to fight the spread of variants as they come to light.            

We cannot afford to be complacent due to declining case rates. After months of declining case rates, India is now experiencing a sudden spike in cases across five different states where an Indian variant N440K has been identified. I have also written about how the variants are linked to a spike in cases across Europe. We must learn from these examples and take them as a warning for what could occur in the U.S. if we do not move quickly to implement new public health measures.