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About the series
Last week, Dr. Anthony Fauci said that the United States is exiting the pandemic phase of COVID-19. Then he walked back the statement and said, “How close are we to the end of this pandemic?” is really an “unanswerable question.” Despite this mixed message, we certainly are in a better place than a year ago, with more immunity, widespread availability of home testing and increasing availability of potent antiviral medications.
In regard to Dr. Fauci’s “misstatement,” the truth is most people are behaving as if the “acute phase” of the pandemic is over. Fewer people are wearing masks, although those who are masked are more likely wearing N95 and KN95 masks. The airlines were back to pre-pandemic passenger capacity in March. Meanwhile, restaurants, movies and museums are sometimes crowded. Nonetheless, I’m still learning of friends and colleagues who are newly infected, but they are generally not getting exceptionally ill.
Despite these trends, this is not the first time that some have suggested that the pandemic is becoming less deadly, so we will need to see how the pandemic evolves over the coming months as the immunity from the December-January Omicron wave starts to wane.
The Centers for Disease Control and Prevention (CDC) reported that in February, 58% of Americans had antibodies showing that they had had COVID-19, up from just 34% in December. About three-quarters of children 17 and under had antibodies showing they previously had COVID-19.
During December 2021–February 2022, overall U.S. antibody rates increased from 33.5% to 57.7%. Over the same period, antibody rates increased from 44.2% to 75.2% among children aged 0–11 years and from 45.6% to 74.2% among persons aged 12–17 years. Antibody rates increased from 36.5% to 63.7% among adults aged 18–49 years, 28.8% to 49.8% among those aged 50–64 years, and from 19.1% to 33.2% among those aged ≥65 years.
Source: CDC April 26, 2022
Implications for employers:
The Food and Drug Administration (FDA) last week advised pregnant women and their physicians caution when interpreting noninvasive prenatal screening tests. These tests are also called “cell free DNA tests,” and they evaluate a sample of the pregnant woman’s blood to find fragments of fetal (baby) DNA to find evidence of genetic defects.
These tests are not FDA approved. They are laboratory developed tests that do not require FDA authorization because they are developed and used within a single laboratory. Such tests allow rapid advances (most of the early PCR tests for COVID-19 were laboratory developed tests), but laboratories sometimes overstate the value of the tests that they have devised.
These prenatal tests are often marketed to pregnant women directly or through their obstetricians. These tests require just a blood draw and don’t carry the risks of invasive tests like amniocentesis or chorionic villus sampling, where medical providers insert a needle to collect cells from the fetus. Some laboratories include genetic counseling with the test, although many don’t.
Laboratories offering these tests often declare that they are highly accurate, but the FDA points out that: “Without confirming the results with a diagnostic test, there is no way to know whether the fetus actually had the genetic abnormality reported by the screening test. The FDA is aware of cases where a screening test reported a genetic abnormality and a confirmatory diagnostic test later found that the fetus was healthy.”
Here’s the problem. Many pregnancies have a genetic abnormality that would often lead to miscarriage. But the chances that any given pregnancy has each specific genetic abnormality are very low. Even when a test has high “specificity” (very low false positives), the false positives will still often be far more common than true positives when the diagnosis is rare in the tested population. Positive tests should be confirmed with a test using fetal cells, but many ordering physicians likely misunderstand the likelihood of false positives. Therefore, women who have a positive test may choose to have an abortion of a fetus that is in fact genetically healthy.
New York Times reporter Sarah Kliff reported on these tests in January, and included a literature review showing that over 80% of the positives are wrong for such terrible birth defects as DiGeorge syndrome (heart defects), ap36 deletion (seizures and intellectual disability), Cri-du-chat syndrome (delayed walking and talking), Prader-Willi (seizures and uncontrollable appetite) and Wolf-Hirschhorn syndrome (seizures, growth delay and intellectual disability).
These tests are generally not covered by employer-sponsored health insurance, although some might be marketed directly to employers. In some instances, the ordering obstetrician could bill the patient for such tests and pay the laboratory only a portion of the fee collected, allowing prenatal testing to be a physician profit center.
Employers should resist urges to pay for screening tests that have not received FDA approval and have not been approved by their insurance carriers. We should all be mindful that even highly “accurate” tests will have many false positives when used to screen a population for a rare disease.
Jeff is an internal medicine physician and has led WTW’s clinical response to COVID-19 and other health-related topics. He has served in leadership roles in provider organizations and a health plan and is an Assistant Professor at Harvard Chan School of Public Health.
