The spread – similar to that of a wildfire – of the Omicron variant may have inspired him, like many Californians, to buy some rapid coronavirus test kits, if he could find them, of course.
And if you started to worry that you’ve contracted the pathogen, you may have put one of those kits to use. He carefully cleaned the inside of both nostrils, mixed the sample with a few drops of reagent, placed it on a test strip, and waited 15 minutes to see the results.
But after doing all of that, and sighing in relief or dismay, you may have overlooked the last instruction in the kit: report your results.
Some test kits recommend that you call your healthcare provider. Others ask you to use the quiz builder app.
“Home testing leads to a marked underestimation of the number of cases,” Dr. Robert Wachter, chair of the UC San Francisco Department of Medicine, noted in an email. “Clearly many hundreds of thousands of people are now diagnosing themselves with positive home tests (usually with symptoms) and these are not reported.”
Even if you try to report your results, the information is not likely to move the needle of public understanding of the virus. This is because they are not included in the data that health officials use to produce their reports and policies.
Therefore, the more people who are tested at home, the fewer official figures on new infections and positivity rates will provide an accurate picture of public health.
That’s not necessarily a bad thing, just a warning about the data we trust as we ride through the pandemic.
Experts note that there has always been a disconnect between reported coronavirus case counts and the truth. Because many people who contract the virus experience few or no symptoms, a large number of infections go unreported.
Similarly, test positivity rates tend to rise because the people most likely to come to a testing center are those with COVID-19-like symptoms. Large organizations that require all of their members to be tested regularly invariably have lower positivity rates than sites that only test those who think they might be sick.
Testing more people more frequently, as other developed countries do, could help identify outbreaks and limit their spread. But for different reasons, the increasing reliance on rapid home test kits may not help public health officials in their battle to track and understand the pandemic.
There are several situations that can cause people to use tests. The Centers for Disease Control and Prevention (CDC) suggests conducting a self-assessment “if you have symptoms of COVID-19 or have been exposed or potentially exposed to someone with the disease” (symptoms to look out for, CDC notes , include fever or chills, cough, shortness of breath, fatigue, and sore throat).
Another good time to self-evaluate, the agency cautions, is before meeting with people who are at higher risk of infection, such as those who are not vaccinated, older adults or those with weakened immune systems. Or maybe you want to attend an event that requires a negative result to be submitted.
What to do after the exam is done? If the result is positive, health officials say you should isolate yourself at home, alert people with whom you have been in close contact, and inform your healthcare provider. The Los Angeles County Department of Public Health also has a hotline – (833) 540-0473 – if you have questions, need referrals, or help notifying your close contacts.
A spokeswoman for the department remarked: “We will document and interview those who call us with positive results.” But the entity does not want to be contacted for negative results.
Health officials generally also do not include home test results in confirmed case counts. One reason is that tests inexpensive are antigen tests, while clinics and county testing centers use polymerase chain reaction tests, which are better at detecting infections in their early stages. Then there’s the question of whether people doing home tests use them correctly or report the results accurately.
“Verifying results is a big problem” for rapid home tests, said Gigi Kwik Gronvall, principal investigator at the Johns Hopkins Center for Health Safety. That’s why if you need a coronavirus test result to board a plane, he added, “you need to have a PCR test done in a lab or you can go to a site that could provide you with a test. [de antígeno] verified; someone to do it for you and who knows it was done correctly. “
After some initial confusion, states now report antigen test results that they collect separately from PCR results, Gronvall said.
Santa Clara County Health Officer and Public Health Director Dr. Sara H. Cody agreed with Wachter that the new infections reported by health authorities each day are “an undercount.” But that may not be as big of a downside as it would have been at the start of the pandemic.
Back then, Cody noted, health officials “followed each case very carefully” because “it really mattered to our understanding of the pandemic and to inform our political decisions.” But now, he stressed, “we are in a quite different moment.”
Even with limited evidence, officials know that the case count will rise rapidly due to the Omicron variant. “What is most important to us now is that we measure the resources of our hospital,” he said, to make sure that people who need acute care can get it. And with the high vaccination rates and boosters in the counties, Cody added, it’s hard to know right now how many of those newly infected will eventually need a hospital bed.
Wachter, Cody and other health experts agreed that the focus of policymakers is shifting away from reported case counts toward other measures, such as hospitalizations and positivity rates. Of course, positivity rates vary by excluding home test results. But for Cody it is still significant to have a comparison of one with the other in relation to the rates of positive tests over time.
Santa Clara County has been doing about 20,000 tests a day, and its positivity rate was about 1.5% in early December, the official noted. Until Tuesday, he said, it was almost 10.5%.
Despite the data problems they create, home antigen testing remains an important adjunct to PCR testing, he added. They alert those who need to isolate themselves and “reduce the chances that they will continue to infect others, which is generally important for public health.”
Additionally, according to the Los Angeles County Health Department, coronavirus case counts are not as significant as the trends they reveal. “As with many reportable diseases, the reported numbers never capture all cases,” said a department spokeswoman. “But they have provided us with a trend to better understand what is happening and model what are probably the most accurate numbers.”
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