As we warily head into another Winter and the start of the Holiday travel season, much of the country is seeing a surge in covid-19 transmission as colder weather forces people indoors. However, I suspect that immunity from high vaccination rates or from previous infection will lessen the impact in most communities relative to last year.
Businesses and workplaces face an additional stressor with the looming compliance with the Department of Labor’s Occupational Safety and Health Administration (OSHA) proposed rule requiring all employers with 100 or more employees to ensure staff are:
- Fully vaccinated against covid-19 by January 4, 2022
- Produce a negative test every week prior to returning to work
A hefty fine of $14,000 per individual can be levied against a company if found out of compliance.
Verifying employees’ vaccination status and testing are both fraught with their own technological challenges, but weekly testing for unvaccinated employees will be the more costly and logistically difficult over the long-term.
Almost two years into this pandemic, the US is still sorely behind European countries in providing inexpensive (or free) widespread access to home-based rapid antigen testing. This is despite pledges of $2 billion by the Biden Administration to provide rapid tests at home for Americans. Additional blame also likely lies at the feet of the FDA regulatory agency who delayed approving rapid tests developed by private companies because they wanted tests with almost perfect accuracy out of fear for missing some infections. But, as they say, “perfect is the enemy of good.” If the FDA had been willing to sacrifice some accuracy for speed much earlier in this pandemic, or even during the recent delta variant surge, we could have significantly reduced the rate of transmission in this country.
It was this emphasis on an accurate test that led to a reliance on more time-consuming, laboratory-based PCR tests. While they are excellent for amplifying and detecting even low levels of viral RNA, this detected virus is not necessarily contagious. In fact, PCR stays positive long after the infectious stage is passed. That is why the CDC does not recommend re-testing in anyone with a confirmed PCR positive test for up to 90 days! If the goal is to keep employees working safely with minimal interruption, reliance on PCR testing can have this unintended negative consequence of staying positive for too long and keeping employees out of the office long after their contagious stage has passed.
If the goal is to medically diagnose someone who recently had covid, then PCR would be the right choice. But PCR testing is not the best test for public health control of viral transmission in the workplace. The goal of asymptomatic screening of people with no reason to think they’re infectious is to identify people who are contagious. This is what rapid antigen testing is good for.
Rapid antigen testing remains poorly understood in this country by the general public, the media, and even public health institutions.
In fact, a CDC report in January 2021 found that rapid antigen tests missed 40% of PCR-positive tests in asymptomatic people. The report and subsequent analysis failed to note that 100% of the misses were in people who had NO culturable (live, contagious) virus. The rapid tests in this study actually correctly identified 100% of the infectious cases.
What we need to remember about rapid antigen testing:
- Presence or absence of symptoms has no impact on test performance
- Its ability to detect infectious individuals with culturable (contagious) virus is as high as for more expensive and potentially delayed laboratory-run PCR tests
- It’s better at identifying contagious/transmissible virus in real-time and minimizing spread and disruption in the workforce
- Serial testing done 2-3 days apart significantly increases the accuracy of the rapid tests in the setting of an outbreak or exposure
- Workplace reliance on laboratory-run PCR tests during a community surge in transmission, for example, has historically led to turnaround times exceeding 5-10 days in some regions
The second key component of an employer-sponsored weekly rapid antigen testing is certifying the results. Employees should not simply be given the tests and told to test themselves at home or find a proctor. Testing can be directly observed
- By the employer at work
- Via a certified Telehealth Proctored session at home (or work)
But if the goal is to NOT have infectious employees show up at work, the best option is rapid antigen home testing with verified proctor use and reporting results. Few companies will want to turn themselves into on-site testing laboratories either. This safely takes the testing off-site and removes the chance for interrupting operations.
One potential wrench in this plan is the limited supply of rapid tests. As part of that $2 billion pledged for testing, the Administration aims to have 200 million rapid tests available to Americans each month. There will certainly be a scramble by companies to both verify vaccination status and procure enough tests with associated proctoring as soon as possible.
By: Dr. Michael Daignault
Chief Medical Advisor, Reliant Health Services