Wednesday, April 28, 2021

No matter where you stand politically, get vaccinated against COVID-19

Here is a public service announcement from several Republican members of Congress who are also health professionals that has been garnering praise across partisan lines. The bottom line is: the more people who do their part and get vaccinated, the sooner everyone will benefit by re-gaining the freedom to return safely to in-person activities that they enjoyed before the pandemic changed everything.

Monday, April 26, 2021

Resuming use of the J&J COVID-19 vaccine is the right call

After a 10-day pause to review safety concerns about the Johnson & Johnson (Janssen) COVID-19 vaccine, the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention (CDC) announced late on Friday that they had accepted the recommendation of the Advisory Committee on Immunization Practices to resume the vaccine's use with a new warning about the extremely rare risk of thrombosis-thrombocytopenia syndrome (TTS).

From a public health perspective, this decision was unsurprising. Although sufficient supplies of two other COVID-19 vaccines are available to vaccinate every adult in the U.S., these mRNA vaccines require two doses (delaying their protective effects by 3-4 weeks compared to the single dose J&J vaccine) and have storage and handling requirements that are challenging for primary care practices. As I argued in a previous post, reaching patients who are hesitant to be vaccinated will require a relationship with a trusted clinician that doesn't exist at a mass vaccination site or a chain pharmacy. During the J&J vaccine pause, 10 million doses were sitting in refrigerators rather than going into arms. Based on a modeling study (slides 38-48), the CDC estimated that resuming J&J vaccination could achieve the goal of vaccinating every American adult who desired a COVID-19 vaccine 14 days earlier than not resuming, as well as preventing 1,435 deaths and 2,236 intensive care unit admissions over a 6-month period with 26 additional episodes of TTS.

When I'm counseling a patient in my office, though, public health benefits usually aren't the main motivating factor in the decision to be vaccinated. So let's drill down to the risks and benefits of J&J vaccination for women ages 18-49. For this group, the risk of TTS from J&J vaccine is 7 in 1,000,000, or about 1 in 143,000 persons. Using this risk estimator from The Economist, the risk of death from COVID-19 in 40 to 50 year old women without other risk factors (e.g., asthma) ranges from 1 in 250 to 1 in 1000. Let's say 1 in 500 for all unvaccinated persons in this age group for simplicity's sake. Of course not all of them will contract COVID-19, but it's reasonable to assume, based on serology surveys and the lifting of social distancing and mask mandates across the country, that at least 1 in 4 of them is likely to be infected by the end of this year. That means their risk of dying from COVID-19 in 2021 is 1 in 2000.

What about younger women? Per the CDC website, 30-39 year olds are about 3 times less likely to die from COVID than 40-49 year olds, while 18-29 year olds are about 10 times less likely.

Let's assume that J&J vaccination reduces COVID-19 deaths by at least 75% (my best guess based on the Phase 3 trial results, which didn't accrue enough deaths to precisely calculate mortality benefits, but was 76%-90% effective against severe/critical disease). So, for women younger than 30, their risk of COVID death in 2021 is about 1 in 20,000. This would fall to 1 in 80,000 after vaccination, preventing 1 in 26,667 deaths, compared to a risk of TTS of 1 in 143,000. For women age 30-39, risk of COVID death is about 1 in 6000 (1 in 24,000 after vaccination, preventing 1 in 8000 deaths), compared to a risk of TTS of 1 in 143,000. For women age 40-49, risk of COVID death is 1 in 2000 (1 in 8000 after vaccination, preventing 1 in 2667 deaths) compared to a risk of TTS of 1 in 143,000.

Another way to look at these numbers: for each case of TTS that occurs due to J&J vaccine in women age 18-29, 30-39, and 40-49, respectively, the numbers of COVID-19 deaths prevented would be 5, 18, and 54.

In summary, J&J vaccine being better than no vaccine, even for healthy women in their 20s with the lowest potential benefit, doesn't look like a close call. And the risk of death from TTS associated with the vaccine is no more than 20%, and should be lower in the future since doctors now know not to treat it with heparin, which can make it worse. Finally, remember that we are discussing two very rare outcomes: a young woman receiving COVID-19 vaccine most likely won't have her life saved from it or experience TTS. That's where the public health benefits of everyone being vaccinated come back in: by decreasing transmission, vaccination reduces the risk of exposure for other people at substantially higher risk of hospitalization and death, and it accelerates the timetable when we can safely "go back to normal" and fully reap the physical, emotional and economic benefits of widespread immunity to the coronavirus.

Tuesday, April 13, 2021

Premature adoption of 3D mammography threatens study that aims to prove its value

Although digital breast tomosynthesis (DBT; 3D mammography) was approved by the U.S. Food and Drug Administration a decade ago and has since been rapidly adopted by breast imaging centers, no studies have shown that it is more beneficial or less harmful for breast cancer screening than traditional digital mammography. In a Diagnostic Tests review in the April 1 issue of American Family Physician, Drs. Kathleen Barry and Chelsea Evans noted that DBT offers a "modestly increased cancer detection rate" and lower recall rate, but also costs about 40% more per test and exposes patients to a higher dose of radiation. It is unclear if additional cancers detected by DBT would have eventually become symptomatic, and "no studies have evaluated mortality as an outcome in women screened with DBT compared with digital mammography."

To address these important questions, in 2017 the U.S. National Cancer Institute (NCI) and the Canadian Cancer Trials Group launched a $100 million randomized trial, TMIST (Tomosynthesis Mammographic Imaging Screening Trial). With a planned enrollment of 165,000 women at 100 North American clinical sites, TMIST was designed to compare the incidence of advanced breast cancer after 4.5 years of follow up in women receiving either digital mammography or DBT. However, by early 2020, investigators had managed to enroll fewer than 23,000 women and were forced to expand to include overseas sites in Asia and Europe. The reason, according to an article in Medscape: already convinced that DBT was a superior technology, large numbers of U.S. and Canadian radiologists were declining to participate. Then the COVID-19 pandemic hit, further hindering recruitment efforts.

Meanwhile, a national study of Breast Cancer Surveillance Consortium sites found substantial racial and ethnic disparities in DBT access, with Black, Asian, and Hispanic women significantly less likely than White women to be screened at a facility with DBT or to receive DBT if the facility offered both DBT and digital mammography. If DBT is truly superior to digital mammography, this apparent disadvantage may worsen existing disparities in breast cancer outcomes. If it isn't, then widespread DBT use is unnecessary and wasteful.

After the NCI director suggested in the fall of 2020 that the "feasibility and relevance" of TMIST was in jeopardy, a working group was formed to reevaluate the trial. In its report released last month, the group recommended that the trial continue, but with protocol revisions that included reducing the sample size to 102,000 and developing specific targets for enrolling women from racial and ethnic minority groups. Unlike European trials that are also evaluating DBT, the group noted, TMIST is the only study that is representative of the U.S. population, includes women younger than age 50, and includes multiple rounds of screening.

In a 2019 commentary, Drs. Joy Melnikow and Joshua Fenton observed of DBT:

Diffusion of medical technology ahead of definitive evidence is common in the United States. ... Societal attitudes that place high value on innovation and technology create a fertile environment for the rapid adoption of novel but unproven interventions. ... When the evidence from randomized clinical trials catches up, interventions shown to add little value to previous approaches are often already embedded in practice, widely covered by health insurance (sometimes by mandate), and difficult to withdraw.

Initial findings from TMIST will be available in 2027 at the earliest if investigators can reach its lower enrollment goal. As radiology facilities across the country continue to "upgrade" from digital mammography to DBT and more states mandate insurance coverage of the newer but unproven technology, I'm not optimistic that this important study's findings will have beneficial effects on clinical practice.


This post first appeared on the AFP Community Blog.

Thursday, April 8, 2021


I have started asking every patient I see, for whatever reason, if they have received or intend to receive one of the three available U.S. vaccines against COVID-19. In less than two weeks, every adult in every state will be eligible to get the shots, and in the next few months the Pfizer vaccine should become available to children as young as age 12. There is no question in my mind that getting vaccinated as soon as possible is the right choice to protect my patients and their loved ones and communities from the ravages of the virus. But like most primary care physicians, I don't have access to a supply of vaccines for use in my office - instead, I must direct patients to a website to sign up for an appointment to get it at another time, somewhere else. And for vaccine-hesitant patients or those who for whatever reason are unable to find the time to do this, this obstacle may leave many unvaccinated who (at least when they saw me) were perfectly willing to get the shot. In a recent Medscape commentary, I argued why "it's time to hand the [vaccine supply] baton to primary care for the final leg of the race to end this pandemic."

I ran track relays in high school: the 4 X 400 meters and 4 X 800 meters. The latter distance is long enough that baton-passing technique makes little difference in the final result, but in the shorter relay (just short of a mile in total) it matters. We runners on deck were taught two techniques: accepting the baton from a standing start or a running start. A standing start usually ensures a clean exchange, but the runner then loses time by being unable to accelerate until the baton is in hand. A running start ensures that momentum transfers smoothly from one runner to the next, but if not executed precisely, it can result in a botched handoff (either a dropped baton or disqualifying exchange outside of the legal zone), dooming the team's hopes. The running start also requires a lot more practice to get right.

What I and family physician colleagues are seeing across the U.S. right now, as primary care practices are gradually becoming involved in vaccination efforts in Maryland and other states, is handoffs from a standing start. Even though many practices went to great lengths to identify and reach out to their patients at the highest risk of complications in anticipation of being able to administer vaccines (running start), the belated recognition by the federal government and state health departments of their critical role in reaching more reluctant patients has forced them to halt these efforts while they wait for adequate supplies to trickle in. This is a huge lost opportunity, and I fear that this lack of coordination between public health and primary care will result in unnecessarily prolonging the pandemic.