A game changing idea that could allow our children to safely go back to school is the subject of a Harvard study. Boston needs to be the location where this is implemented first. Let me explain:
An April 1 article in the NY Times by Dr. Joshua Rabinowitz and Caroline Bartman “These Coronavirus Exposures Might Be the Most Dangerous” noted that “the importance of viral dose is being overlooked in discussions of the coronavirus. As with any other poison, viruses are usually more dangerous in larger amounts.”
This observation about the impact of viral dosage stuck with me because a very close friend died a few days later from COVID-19 after spending several hours doing two nurse visits with an older man who had the virus. And so, it wasn’t a surprise to hear on the July 15 edition of “This Week in Virology” aka TWIV (https://www.youtube.com/watch?v=kDj4Zyq3yOA), that people who have been infected with coronavirus are only infectious to others during a period when their “viral load” is high.
TWIV guest Dr. Michael Mina, a Harvard infectious disease specialist, connected viral load to the way in which testing is done in the United States, and came up with an idea on how the U.S. could get control of the virus more quickly. This could have a major impact on how children could return to school. He describes the research in a soon-to-be-published article, written by a group from Harvard and the University of Colorado, entitled “Test sensitivity is secondary to frequency and turnaround time for COVID-19 surveillance.”
The standard test for COVID-19 is what is called a RT-PCR test, which costs about $100 and measures whether there is coronavirus RNA in the bodily fluid sample. Coronavirus infection starts quickly, and exponentially grows in the body, before trailing off over what can be a few weeks or even months. But scientists now know that transmissibility of the virus is related to the load of the virus, which decreases over a shorter period of time than initially thought. It is in the early period, during which time an infected person can be asymptomatic, that one is infectious.
The PCR test typically cannot be administered at home and takes 3-9 days to get results. It takes this long because it has a high degree of “sensitivity,” which means that it can trace extremely low amounts of virus RNA. The problem is that, by the time the results are known, most people with COVID-19, though still infected, have passed their infectious state and are left with fragments of RNA, not enough to cause transmission of the virus. Or, to put it another way, the current tests we are using are not solving our COVID transmission crisis.
Dr. Mina noted that the US has had earlier tests with less sensitivity, such as the Abbott ID Now Test, but they had low sensitivity, and so were not used much. But Mina stressed that the low sensitivity tests measure the period when the person is infectious. “Maybe we only need a really crappy test … if it’s cheap enough to use it frequently, then it doesn’t detect less than 5% of people when they’re transmitting, it detects 85% of people when they’re transmitting. That’s a huge win over what we have right now.”
Beyond the advantage of low sensitivity tests being effective for measuring when a patient with COVID-19 is infectious, it is also extremely cost effective at $1-2 per test, and can be done at home. The test is a piece of paper or cardboard painted with monoclonal antibodies, onto which you spit. Results are available in ten minutes. Yes, ten minutes. Think pregnancy home testing except this is even cheaper and easier to use.
What does this mean for getting children back in school quicker?
Schools can provide parents with free home tests that determine on a daily basis that if the child has the virus and is contagious. At $1-2 per test, it becomes very affordable to cities and towns, and if the child tests positive, the child stays home, if not, the child goes to school. Since the test would be administered often, a missed reading would likely be picked up within a day or two. The immediacy of identifying those with the virus who are infectious could put the lid on transmission in school communities.
Boston needs to be the lead on this.
Beyond this, this idea has great potential across the country. The plan that public health officials put together in the first unsure months of COVID-19 was to get control of the virus through social distancing, masks and good hygiene. This was to be followed by an enormous amount of testing that would allow our country to rapidly identify those with the virus, so that they could be quarantined, and all their contacts could be traced to ensure that the virus had limited spread.
The cost of the test seemed to be the major issue that prevented this from happening. Perhaps that day has come.
Bill Walczak of Dorchester is the co-founder of the Codman Square Health Center and was a candidate for Mayor of Boston in 2013. His column appears weekly in the Reporter.