In This Issue
Wastewater testing and pre-flight testing both “work”
New insights into bats’ uncanny ability to tolerate viruses
Don’t judge a meta-analysis by its cover
New and Noteworthy
The first at-home test for COVID-19 and flu is here - sort of.
Last Friday, the FDA granted an EUA to Lucira for the very first over-the-counter at-home combination COVID and flu (A and B) test. Using loop-mediated isothermal amplification (LAMP) technology, the test can provide a diagnosis in 30 minutes. According to the EUA, it correctly correctly identified 99.3% of negative and 90.1% of positive flu A samples, 99.9% of negative flu B samples, and 100% of negative and 88.3% of positive COVID samples. (Of note: Since there were virtually no flu B cases this year, Lucira validated that part of the test in contrived specimens. The company is required to continue to collect samples in real-world settings to detect flu B.)
So we finally have the first multiplex respiratory test that includes COVID-19! So exciting, right? But there’s an O. Henry-style twist to this story: Lucira’s announcement came two days after the company declared bankruptcy and announced that its assets were up for sale.
How the bankruptcy announcement will impact product sales is not clear yet. Given that product launch typically takes at least three weeks, it is hard to imagine that the test will be widely available in the US for this flu season. (Wondering what it will cost? No announcement yet, but the same test was authorized in Canada in August 2022 and priced at $70 there.)
Commentary: Is a combination OTC home COVID / flu test a good idea? We think yes, especially given the many overlapping symptoms but very different treatments. However, the US needs to further develop and widely publicize its reporting system for OTC test results - and convince users that it does not violate their privacy. And physicians and payers need to acknowledge that these tests work - and not require another test before considering treatment.
Airplane wastewater testing works - and so does pre-flight testing
The results of CDC’s initial foray into airplane wastewater testing are in - with good news for researchers and bad news for travelers. The good news: CDC now has evidence they trust that airplane wastewater testing is a cost-effective way to keep an eye on the variants entering the country. The bad news: Of the 80 international flights into JFK that were tested, 65 (81%) were positive for COVID-19.
These flights were all tested in August and September 2022, a full two to three months after the US rescinded its requirement for international travelers to present a negative COVID test (or proof of prior infection in the past 90 days) within 24 hours of boarding a flight into the country. If the requirement hadn’t been dropped, the results might have been quite different. According to another CDC study, which looked at 3,049 pooled (28,056 individual) samples collected from volunteers disembarking from international flights between March and September 2022, “the pre-departure testing requirement was associated with 52% lower post-arrival SARS-CoV-2 positivity.”
Commentary: We stand corrected - based on this study’s results, while pre-departure COVID testing is not an ironclad barrier to virus entry, it does appear to be more than hygiene theater.
Instead, it’s a good reminder: We need to stop expecting, promising, or demanding 100% guarantees, especially when it comes to public health. Instead, we should remember the Swiss-Cheese Model, in which multiple imperfect layers of protection work better than relying on any one layer alone. The difficulty, especially at this stage, lies in finding the balance - different people feel comfortable with different levels of protection, and are willing to tolerate different levels of inconvenience to get it.
Food for Thought
Bats handle viruses better than we do - and now we have the tools to find out how.
Did you know that bats can carry and spread viruses like SARS-CoV-2 and Marburg without getting sick themselves? Whether you think bats are cool or freaky, that’s a bit of a scary thought.
In a recent Cell paper, researchers created induced pluripotent stem cells (the first time that had been done) from two different bat species to enable further research into what makes bats unique. They found an incredibly wide array of partial and complete viral genomes integrated throughout the bat genome. (Shades of how the CRSPR/Cas immune system works to counter previously encountered viral threats to bacteria - and pass that ability to their descendants?)
Among the long list of results the paper describes (seriously, it’s impressive), the team demonstrated that the viral genomes don’t just lurk inside bat cells - they create viral proteins. Exactly how that activity functions against viral infection is still unclear.
Commentary: With the creation of these cells, we now have a way to continue investigating bats’ superpowers. The hope is that it will give us insight not only into the danger that bats represent as a viral reservoir, but perhaps also into their unique ability to live with viruses rather than succumbing to them. This information could then potentially inform the tactics we use against viruses that plague humans.
Meta-analyses are only as good as the studies they review.
A week ago, The New York Times published an opinion piece with the headline “The Mask Mandates Did Nothing” as a basis for a broad indictment of the CDC, its leadership, the failure of science, and public health mandates in general. The article is based on a recent 326-page Cochrane Library Review entitled “Physical interventions to interrupt or reduce the spread of respiratory viruses,” which concluded that “Wearing masks in the community probably makes little or no difference to the outcome of influenza-like illness”.
However carefully a meta-review is carried out, its headline conclusions submerge a few really relevant studies under an always larger number of mediocre ones. The primary advantage of meta-studies is a carefully curated and annotated bibliography of relevant evidence. For those interested, Tomas Pueyo published a thorough rebuttal in his Uncharted Territories blog - detailing how the NYT conclusions were inconsistent with the details of the best of the evidence evaluated by Cochrane.
Commentary: The general resistance to public health measures is not new (see The London Times, 1854), and restrictions must be carefully evaluated before freedoms are curtailed. But masking still remains the best protection against airborne pathogens like SARS-CoV-2. And we’re not the only ones who continue to think so - despite the Cochrane Review paper and the breathless headlines it’s generated.
Quick Hits
Good and bad news on the 2022/23 avian H5N1 flu epidemic - A widely publicized first human death from avian flu in Cambodia turned out to have resulted from a locally endemic version of the virus, not the variant circulating worldwide. However, the USDA has found 12 more mammal species who are susceptible to the worldwide variant, maintaining concerns about the possibility of eventual transmission from birds to humans.
EUA Update
The FDA issued 7 new EUAs, 20 amendments to existing EUAs, and 4 revocations in February. Data is available at TestingCommons.com
New EUAs (7):
COVID Molecular (2): The HFI Laboratory at Boston University | ADL Diagnostics
COVID Antigen (2): GenBody COVID-19 Ag Home Test | COVI-Go SARS-CoV-2 Ag Self-Test
Respiratory multiplex (COVID and Flu) (3): Lucira COVID-19 & Flu Home Test | BD Respiratory Viral Panel for BD MAX System | LumiraDx SARS-CoV-2 & Flu A/B RNA STAR Complete Assay
Amendments to Existing EUA’s (20):
COVID Molecular: 9
COVID Antigen: 8
Respiratory multiplex (Flu and COVID): 3
Safety Communications (4):