Measles outbreaks and the future of public health

In early March, a one year-old boy living in a shelter in Chicago was diagnosed with measles. Since measles is a highly contagious virus, more than 2000 shelter residents, many without confirmed histories of measles vaccination, were considered to be exposed. Over the next 3 days, the Chicago Department of Public Health (CDPH) swung into action, vaccinating 882 residents and confirming previous vaccination status in several hundred more, resulting in an estimated measles, mumps, and rubella (MMR) vaccine coverage of 93%. Nonetheless, in the next two months, 57 more cases of measles had been diagnosed among people residing in or having contact with residents of the shelter. A dynamic disease simulation model from the Centers for Disease Control and Prevention (CDC) estimated that in the absence of mass vaccination and case finding by CDPH, there was a 69% probability that this single infection would have led to more than 100 new measles cases.

The outlook for measles in the next decade in the U.S. is mixed, at best. Driven by the COVID-19 pandemic, vaccine skepticism and anti-vaccine sentiment has led to increases in religious and philosophical exemptions, causing the national kindergarten vaccination rate to fall to 93% in 2021-2022. Each percentage point decline increases the risk of a measles outbreak, as illustrated by the CDC's National Center for Immunization and Respiratory Diseases, with 93% MMR vaccination coverage associated with a 36% risk that a single infectious child could create an outbreak at a school with 100 children.

Unfortunately, decreasing childhood vaccination rates were not the only negative effect of the pandemic. The compelling PBS mini-series "The Invisible Shield" juxtaposes the historical successes of public health officials in controlling diseases and saving lives with the angry and occasionally violent pushback they received for ordering business closures and masking mandates to slow the spread of COVID-19. A recent Health Affairs article documented 112 judicial decisions from 2020-2023 that constrained public health's legal powers. As a result, the health commissioner for Columbus, Ohio was unable to close a daycare center where a measles case was reported in 2021, and a county in Michigan came close to shutting down the entire county health department over a dispute about masks.

An even bigger threat to public health is awaiting a decision from the Supreme Court:

On January 17, 2024, the US Supreme Court heard oral arguments in 2 combined cases, Loper Bright Enterprises v Raimondo and Relentless, Inc v Department of Commerce, that will determine the fate of Chevron deference, a bedrock principle of administrative law that obligates courts to defer to an agency’s reasonable interpretations of ambiguous statutes. ... Agencies like the FDA and CMS have, for decades, regulated medicine and public health in reliance of these principles.

If the Supreme Court decides that this deferential statutory framework is unconstitutional, it would effectively open every federal health regulation that does not derive directly from specific legislative language (the vast majority of thousands and thousands of regulations) to a lawsuit, and it would put the burden on a dysfunctional Congress to account for "all possible regulatory scenarios and unforeseen circumstances" in writing unambiguous legislation. This would be a disaster.

I wonder how federal and state governments would respond if public health actions became necessary to protect people from H5N1 ("bird flu"), which so far has only been confirmed in 3 dairy workers this year but has likely infected many more? So far H5N1 has only caused mild symptoms in humans, but the fact that this virus has spilled over from cows to people and little surveillance is being done in to track its spread in either population is worrisome.

Treating elevated BP in the hospital: more harm than good?

In an inpatient setting, elevated blood pressure (BP; > 140/90 mm Hg) is very common; a 2011 systematic review of nine cohort and cross-sectional studies found a prevalence of 51% to 72%. A recent systematic review found that among 14 international clinical practice guidelines on hypertension, none addressed inpatient BP goals or management of moderately elevated BPs (140–179/90–119 mm Hg) in the hospital. Although the long-term benefits of outpatient BP control are well established, it is not clear whether initiating or intensifying antihypertensive therapy in the hospital is necessary or beneficial. In fact, two large cohort studies have suggested that such therapy may cause more harm than good.

The first study evaluated adults hospitalized in 2017 for noncardiac diagnoses at 10 hospitals in the Cleveland Clinic health system; 78% had at least one elevated BP reading prior to discharge. About 1 in 3 of these patients received acute hypertension treatment, defined as “administration of an intravenous antihypertensive medication or a new class of an oral antihypertensive treatment.” After controlling for potential confounding factors, treated patients had statistically higher rates of acute kidney injury (10.3% vs. 7.9%) and myocardial injury (1.2% vs. 0.6%) than untreated patients. In patients whose antihypertensive medications were increased at discharge, BP control did not improve in the following year.

The second study focused on patients 65 years or older in a Veterans Health Administration hospital for noncardiac diagnoses between October 1, 2015, and December 31, 2017, who had elevated BPs within 48 hours of admission. Using a propensity score overlap weighting analysis to control for confounders, patients who received intensive BP treatment (defined the same as “acute hypertension treatment” in the first study) during this time period were more likely (8.7% vs. 6.9%) to experience a composite outcome of inpatient mortality, intensive care unit transfer, stroke, acute kidney injury, B-type natriuretic peptide elevation, and troponin elevation.

In an article in the February 2024 issue of American Family Physician, Dr. Robert Gauer and colleagues advised taking a conservative approach to elevated BP in the hospital. Clinicians should address causes of transient BP elevations (e.g., pain, agitation, anxiety, fluid overload) rather than reflexively treating the numbers. Noting that “hospitalized patients with elevated BP often see a decrease of 20 mm Hg with subsequent measurements,” the authors suggested that 30 minutes of rest, rather than medications, should be first-line therapy. Patients with severe asymptomatic hypertension (BP > 180/110 mm Hg) should be treated with oral therapy only if they are at high risk for inpatient complications and if secondary causes have been excluded or addressed. Intravenous therapy should generally be avoided.

**

This post first appeared on the AFP Community Blog.

19th century mental disorders and the American Civil War

Earlier this week, I gave this lecture as part of the "Lunch and Learn" webinar series sponsored by the Lancaster Medical Heritage Museum. I appreciated the opportunity to combine my interests in history and medicine to discuss how post-traumatic stress disorder manifested in former Civil War soldiers and its historical and present-day treatment.

Are beta-blockers always beneficial after a myocardial infarction?

Prescribing beta-blocker therapy to a patient after a myocardial infarction (MI) is thought to reduce recurrent MI and mortality and has been a reportable quality measure for decades. A 2000 American Family Physician article on this topic, “Optimizing beta-blocker use after myocardial infarction,” implied that this intervention was settled science. However, the benefits of beta-blockers were established in studies mostly conducted in the 1980s, when most diagnosed MIs caused significant left ventricular systolic dysfunction, and prior to the use of high-sensitivity cardiac troponin tests, percutaneous coronary interventions (PCI), thrombolytics, high intensity statins, and renin-angiotensin-aldosterone system antagonists.

A 2014 meta-analysis of 12 randomized trials performed in the “reperfusion era” reexamined the benefits and harms of adding beta-blockers to modern interventions in patients after MI. Beta-blockers did not improve mortality, and their benefits were limited to the first 30 days. An AFP POEM synopsis reported that while beta-blockers reduced the risk of recurrent MI (number needed to treat = 209) and angina symptoms (NNT = 26), they also increased rates of heart failure (number needed to harm = 79) and cardiogenic shock (NNH=90).

On the other hand, a 2020 Cochrane for Clinicians on beta-blockers after suspected or diagnosed acute MI, while noting that “most trials were conducted before the introduction of what is now considered standard reperfusion therapy,” found reduced risks of MI, cardiovascular and all-cause mortality even in patients who had not received PCI, thrombolytics, or coronary artery bypass grafting. Consequently, the authors recommended, “family physicians should continue to incorporate beta-blocker therapy in the care of patients with a history of MI.” The current American College of Cardiology / American Heart Association guideline for management of patients with chronic coronary disease splits the difference. As stated in a POEM in the March 2024 issue, “Long-term beta blockers are no longer routinely recommended and should be limited to patients with heart failure, myocardial infarction in the past year, or another indication.”

To clarify the effects of beta-blocker therapy post-MI, a randomized, open-label trial published earlier this month assigned more than 5,000 patients with an acute MI and preserved left ventricular ejection fraction (LVEF) of at least 50% to long-term therapy with metoprolol or bisoprolol or no treatment. After a median of 3.5 years, there was no difference between the groups in the primary composite outcome of death from any cause or new MI. Other potential benefits and harms, including hospitalization for atrial fibrillation or heart failure and hospitalization for bradycardia, hypotension, or syncope, were also statistically similar between the groups. Although these findings suggest that beta-blockers have no effects in post-MI patients without heart failure, an accompanying editorial observed that several more trials addressing this important clinical question will be completed in the next few years.

**

This post first appeared on the AFP Community Blog.

STFM Research Paper of the Year

Thanks to Dr. Laura Blinkhorn for snapping this photo, since I wasn't able to travel to the Society of Teachers of Family Medicine conference this year. It's an honor to be recognized!