Benefits of COVID-19 vaccination in persons with past infection

Since the first COVID-19 vaccine received authorization for emergency use in December 2020, physicians and the public have vigorously debated whether infection-acquired ("natural") or vaccine-mediated immunity provides better protection against future infection and severe illness. The answer may never be known for certain, as it's hard to imagine a research ethics committee approving a trial that intentionally exposes immunologically naive people to a potentially lethal infection. A more important clinical question is: does getting vaccinated after recovery from COVID-19 provide additional benefits? Currently, the Centers for Disease Control and Prevention recommends routine vaccination in all persons aged 5 years or older, regardless of their history of past infection.

Two large cohort studies published earlier this month provided the strongest evidence to date that the answer is yes. The first study used electronic medical records from a health care organization covering more than half of the population of Israel to identify 149,000 patients age 16 years or older who had recovered from documented SARS-CoV-2 infection at least 100 days earlier and had not yet received COVID-19 vaccination as of March 1, 2021. 56% of these persons received at least one dose of BNT162b2 (Pfizer-BioNTech) vaccine by November 26, 2021. 2,168 of those who remained unvaccinated (3.3%) were reinfected during the study, compared to 354 of the vaccinated patients (0.4%). After adjustment for sociodemographic factors and coexisting illnesses, the estimated vaccine effectiveness was 82% for patients aged 64 years or younger and 60% for patients aged 65 years or older. A secondary analysis showed no difference in protection between one or two vaccine doses.

A second study in a highly vaccinated cohort of 35,768 health care workers in the United Kingdom tracked primary infections and reinfections between December 7, 2020 and September 21, 2021. Most participants received two doses of BNT162b2 (Pfizer-BioNTech) vaccine; 8% received the single-dose ChAdOx1 nCoV-19 vaccine (AstraZeneca). In previously uninfected participants who received the second dose of BNT162b2 six weeks or more after the first dose, adjusted vaccine effectiveness was 85% up to 73 days after the second dose but declined to 51% after 200 days. In comparison, adjusted effectiveness of the ChAdOx1 nCoV-19 vaccine was only 58% up to 73 days. In 6,169 participants who had COVID-19 prior to the study, long-term (>1 year) protection against re-infection was 69% in unvaccinated persons but remained high at 94% in persons who received one or two doses of BNT162b2.

Acknowledging some differences between the populations and the predominant variants circulating during the respective study periods, the results support the following conclusions. First, re-infection in unvaccinated persons is relatively uncommon during the first 9 months after a primary infection (1 in 30 in the Israeli study) but becomes more likely after 1 year (per the U.K. study). Similarly, the effectiveness of the initial two doses of BNT162b2 vaccine in preventing COVID-19 declines after 6-7 months, supporting booster doses. However, patients with past infections who subsequently receive one or two doses of BNT162b2 have sustained high levels of protection ("hybrid immunity") against re-infection for at least one year. In an editorial in The Guardian, Dr. Eric Topol recently argued that these and other data support re-defining "fully vaccinated" to include recovery from past infection plus a single dose of an mRNA vaccine.

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This post first appeared on the AFP Community Blog.

Screening for atrial fibrillation, revisited

In 2018, the U.S. Preventive Services Task Force (USPSTF) concluded that the evidence was insufficient to assess the balance of benefits and harms of screening for atrial fibrillation (AF) with electrocardiography. However, the proliferation of wearable devices capable of detecting brief episodes of cardiac arrhythmias raised the question of whether screening high-risk patients outside of the office, analogous to home blood pressure monitoring, might prove beneficial. In a scientific statement, the American Heart Association discussed the knowledge gaps regarding the risk of stroke and benefits and harms of initiating long-term anticoagulation in persons with subclinical AF.

Two randomized screening trials published in 2021 aimed to fill these gaps, but instead arrived at mixed conclusions. In the LOOP Study, 6004 Danish adults aged 70 to 90 years with stroke risk factors were randomized in a 1:3 ratio to receive an implantable loop recorder (ILR) or routine medical care. ILR participants were contacted if they had atrial fibrillation lasting for at least 6 minutes and recommended to start anticoagulation. Control participants received electrocardiography as needed from their primary care physicians. After a median follow-up of 64.5 months, 32% of patients in the ILR group and 12% of patients in the control group had atrial fibrillation detected, with similar proportions initiating oral anticoagulation. However, there was no significant difference in the primary outcome of stroke or systemic arterial embolism (4.5% of patients in the ILR group vs. 5.6% in the control group). Rates of major bleeding were not statistically different between the groups.

In the STROKESTOP trial, 28,768 Swedish adults aged 75 or 76 years were randomized to receive an invitation to screening with a handheld single-lead electrocardiogram twice daily for 2 weeks or usual care. After nearly 7 years of follow-up, a composite outcome of stroke, systemic embolism, hospitalization for bleeding, or all-cause mortality was slightly less likely to occur in the intervention group (NNT=93), but differences in individual outcomes were not statistically significant.

Reviewing these trial results and additional data, the USPSTF recently updated its 2018 statement and concluded that the evidence remains insufficient to make a recommendation. An accompanying editorial in JAMA Internal Medicine by Drs. John Mandrola and Andrew Foy (who also authored a 2019 editorial on the downsides of detecting asymptomatic atrial fibrillation) noted that the potential benefits of widespread cardiac rhythm monitoring on cardiovascular and stroke risk could be offset by  "misdiagnosis and downstream cascades of care" and that the "work-up of [arrhythmias] can lead to anxiety, iatrogenic harm, and excess health care costs."

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This post first appeared on the AFP Community Blog.

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Update (3/2/22): VITAL-AF, a cluster randomized controlled trial of >30,000 patients aged 65 years or older in Massachusetts General Hospital-affiliated primary care clinics, tested screening for AF with a handheld single-lead ECG (KardiaMobile) during vital sign assessments. Compared to the usual care group, the screened group had a marginally higher incidence of newly diagnosed AF after 1 year, but no difference in the proportion of individuals treated with oral anticoagulants.

How much administration does health care really need?

During my residency in family medicine, one of the faculty was tasked with the challenge of teaching all of us the "practice management" curriculum, trying earnestly to make us understand how much of our time and energy in clinical practice would be consumed by administrative tasks. Even then, it struck me as borderline crazy how non-procedural physicians are paid. At the time I graduated from residency (2004) and for many years afterward, the financial value of an outpatient "evaluation and management" (E/M) visit was determined not only by the complexity, acuity, and number of medical issues addressed, but also by the number of body "systems" discussed and physically examined. Why the latter should have any relationship to how much money a patient and/or her health insurance company pays for an office visit was, and remains, beyond my comprehension.

My colleague and fellow family physician Dr. Ranit Mishori has written for Medscape about why she and many other clinicians have come to hate the review of systems (ROS). Like many others over many years, she pointed out that a comprehensive (rather than focused on the chief complaint or condition being treated) ROS was usually useless and often led to bloated documentation. Nonetheless, each health care organization I've worked for over the years has employed a small army of people whose job it is to make sure that physicians include the ROS and enough physical examination elements to justify coding a higher-level (i.e., higher charge) visit, and to let us know if we're not doing it right.

Last year, the Centers for Medicare & Medicaid Services (CMS) finally simplified their guidelines for E/M visit codes, essentially eliminating the requirement to document more information than clinically useful about the history of present illness, ROS, and physical examination. In FPM, the American Academy of Family Physicians' practice management journal (on whose editorial board I served from 2010-2014), this change was celebrated with articles with titles such as "Outpatient E/M Coding Simplified" and "A Step-by-Step Time-Saving Approach to Coding Office Visits." That a series of several articles was required to explain the simplified guidelines to physicians and common situations such as "Combining A Wellness Visit with a Problem-Oriented Visit" means that practice management curricula aren't going away any time soon, even though the physician who taught me has gone on to a well-deserved retirement. For while some administrative burdens have been lessened, others have been increased, as payment incentives for providing high quality of care require physicians to document other things, such as the reason my 70 year-old patient with end-stage renal disease on dialysis and chronic heart failure doesn't need to have any more screening mammograms. More primary care practices are using medical scribes, in-person or virtual, to document office visits. While that's good to prevent burnout, it remains faintly ridiculous that armies of such people are being employed for a task that adds little actual value to the heath care encounter.

Is there really too much administration in health care? From an objective viewpoint, the answer is absolutely yes, as a recent JAMA commentary observed:

A typical US services industry (for example, legal services, education, and securities and commodities) has approximately 0.85 administrative workers for each person in a specialized role (lawyers, teachers, and financial agents). In US health care, however, there are twice as many administrative staff as physicians and nurses [emphasis mine], with an estimated 5.4 million administrative employees in 2017, including more than 1 million who have been added since 2001.

The commentary went on to discuss the findings of a new report that concluded, amazingly, that "an estimated $265 billion, or approximately 28% of annual administrative spending, could be saved without compromising quality or access by implementing about 30 interventions that could be carried out in the next 3 years." This without any major structural changes in the U.S. health care system - no need to transition to "Medicare for All" or a single-payer model (though either could lead to even greater efficiencies and savings). Companion commentaries explained why U.S. health care administrative expenses are so high (efforts to control care utilization and prices through market-based forces give rise to activities that require the hiring of more administrators) and how administrative simplification can be economically incentivized (because, apparently, wasting $265 billion per year on unnecessary administration isn't incentive enough).

Achieving this logical next step in administrative simplification will, of course, be an uphill battle. To paraphrase Dr. Don Berwick, what some call health care "waste," others call "income." The same certainly goes for those armies of people looking over my E/M coding, the armies of scribes, and the armies of quality of care managers and utilization and cost controllers. The armies of people working in health care today who facilitate transactions and documentation instead of improving the patient's care experience and health outcomes.