Testing of asymptomatic people: a very diminished role
Earlier in the pandemic, before the widespread availability of vaccines, when capacity restrictions and home orders were very common, rapid serial testing of asymptomatic individuals to find out who was infected with a contagious amount of the virus, and therefore a threat to others, was a key unmet need. However, much of the pandemic has unfolded without access to quick and cheap tests that people could frequently self-administer when brushing their teeth each morning. I think the benefit of these tests would have been incalculable in terms of reducing exposures and transmission events but also allowing people to resume some of their activities largely without worrying about infecting others.
With the decline in cases, the percentage of test positivity dropping, and the virus largely decoupled from its ability to cause serious illness, hospitalizations and death, the value of these tests is also shifting. Testing on asymptomatic unvaccinated people will increasingly have diminishing returns as the likelihood of truly positive tests, as opposed to false positives, becomes rarer. A positive rapid antigen test would require confirmation by a more sophisticated molecular test, or other separate antigen test while the person is in limbo, with their life possibly interrupted or interrupted, pending the results. This is particularly relevant for schools, but applies to the general public and also applies to group tests. There is very little reason to test asymptomatic individuals beyond the early facilitation of the unvaccinated end-of-quarantine quarantine exposed to COVID or the unvaccinated international traveler. Fully vaccinated people, as CDC guidelines state, should not be tested unless they are showing symptoms.
Symptomatic tests are always essential
Unlike testing on asymptomatic unvaccinated people, there is, and will remain, a need for clinical testing on those with symptoms. Such tests will still occur years from now, as COVID-19 will still circulate and although it may not cause a hospital crisis, diagnosis will remain standard practice. The virus diagnostic test is already part of the routine respiratory pathogen panels that test patients for multiple infections simultaneously. Additionally, testing is important for identifying new variants of the virus (most of which will be harmless) that may have altered attributes. Symptomatic testing will also help identify clusters of infections and guide public health investigations into activities contributing to the spread in unvaccinated people.
Fomenting a testing revolution
Insufficient response to COVID-19 testing underscores the need to seriously increase the ability to diagnose infectious diseases system-wide – in health care settings, emergency care clinics, doctor’s offices and across the board. home. It should no longer be acceptable to label people as having an undefined viral infection when hiding among these cases could be follow-up viral infections that could inform pandemic planning and improve patient care by facilitating better prescription of antivirals and reducing inappropriate prescription of antibiotics for viral infections for which they have no role.
In addition, the home tests for COVID-19 that have been authorized are an opportunity not to be lost. Indeed, before the pandemic, I started a project focused on understanding the barriers to increasing home testing for a variety of infectious diseases. Home COVID-19 testing, which should still be used by symptomatic people, should be converted to a full FDA license and extended to cover other infectious diseases such as influenza, RSV, strep throat, strep throat, mononucleosis and sexually transmitted infections (there is already one – over-the-counter home HIV test).
COVID-19 testing is here to stay, but will play a very different role as the virus is increasingly denied the ability to cause serious illness or threaten the capacity of the hospital. Symptomatic testing will be a critical ability to maintain and expand to other pathogens, but the value of asymptomatic testing has lost much of its value and will become riddled with problematic false positives as the prevalence of l infection has dropped and the vaccination rate is increasing.
Amesh Adalja, MD, is an infectious disease physician and principal investigator at the Johns Hopkins Center for Health Security. Follow him on Twitter: @AmeshAA.