On May 26, 2020, the Center for Disease Control and Prevention (“CDC”) released its anxiously awaited Interim Guidelines for COVID-19 Antibody Testing (the “Guidelines”). As set forth in further detail below, the Guidelines make clear that COVID-19 antibody testing should not be used to make decisions about returning employees to the workplace.
While the Guidelines detail some encouraging data developed from early studies on antibody testing, several concerns remain. On the encouraging side, the CDC states in the Guidelines that “nearly all immune competent individuals” will develop an immune response following infection with COVID-19 and recurrence of COVID-19 illness “appears to be very uncommon,” suggesting that COVID-19 antibodies may confer at least some short-term immunity. Consistent with this observation, the Guidelines further note that in experiments involving primates, infection and subsequent development of antibodies resulted in protection from reinfection. Additionally, the Guidelines note that antibody development in humans correlates with a marked decrease in viral load in the respiratory tract. According to the CDC, taken together, these observations suggest that the presence of antibodies may decrease a person’s infectiousness and offer some level of protection from reinfection. However, the Guidelines make clear that definitive data are lacking and it remains uncertain whether individuals with antibodies are protected against reinfection with COVID-19, and if so, the duration of that protection and what concentration of antibodies is needed to confer protection.
In addition to these issues, the CDC raises several other concerns in the Guidelines regarding antibody testing. The Guidelines note that some antibody tests can lead to false positive results, when they react with the presence of antibodies to other coronaviruses like the common cold. Moreover, the CDC cautions that certain individuals may not develop detectable antibodies even after infection while others’ levels could wane over time to be undetectable. The timing of antibody tests can affect the result as well; as the CDC notes, the most useful antibodies for assessing antibody response are not present early in infection, and only become detectable 1-3 weeks after symptom onset. Thus, antibody test results may not definitively indicate the presence or absence of current or previous COVID-19 infection.
In light of the continuing uncertainty regarding these issues, the CDC affirmatively states that COVID-19 antibody testing results “should not be used to make decisions about returning persons to the workplace.” The CDC specifically notes that although certain testing can have “high positive predictive value” indicating at least some degree of immunity, “until the durability and duration of immunity is established, it cannot be assumed that individuals with truly positive antibody test results are protected from future infection.” In addition to stating that employers should not use antibody testing to determine eligibility to return to the workplace, the CDC also recommends against using antibody testing to make decisions about admitting individuals to other congregate settings, such as schools, dormitories, or correctional facilities.
Finally, the CDC states that its Guidelines do not affect existing guidance from public health authorities and other governmental agencies on maintaining social distancing and using PPE in the workplace. The CDC notes that healthcare workers and first responders should continue to use PPE even if they test positive for COVID-19 antibodies. Further, while those who test positive for antibodies and do not have a recent history of “a COVID-19 compatible illness” have a low likelihood of active infection, they should still follow general recommendations to prevent the spread of infection.
While this area is rapidly evolving, employers now have affirmative guidance from the CDC that antibody testing should not be used to make decisions about bringing employees back to work. Since the EEOC has largely deferred to the CDC on this issue, employers who condition an employee’s return to work on a positive test for antibodies may be subject to claims by both the individual and the EEOC.