Avian flu virus in raw milk … and other research
BMJ 2024; 385 doi: https://doi.org/10.1136/bmj.q1331 (Published 20 June 2024) Cite this as: BMJ 2024;385:q1331
Avian flu and milk pasteurisation
An outbreak of avian flu in dairy farms in the US has led to three confirmed cases in humans. The first case is thought to be due to infected milk splashing into the eye. A letter in the New England Journal of Medicine describes an experiment to measure the inactivation of the H5N1 avian flu virus in milk when pasteurised. The authors found that heating milk spiked with H5N1 to 72°C—the typical temperature for pasteurisation—led to a rapid reduction in infectious virus, which remained detectable for only 20 seconds. However, with the minimum time for pasteurisation at this temperature being only 15 seconds, the authors call for more research on H5N1 in dairy production including in real world conditions with milk from infected cows.
N Engl J Med doi:10.1056/NEJMc24054
Colchicine for stroke
Colchicine tablets cost about 2 pence each, so finding funding for a large randomised controlled trial that can detect small but clinically relevant improvements in outcomes must be challenging. The authors of a new study in the Lancet managed it though, and 3154 people with non-severe, non-cardioembolic ischaemic stroke or high risk transient ischaemic attack were randomised to either colchicine 0.5 mg daily or usual care. However, they ran out of money (the trial was stopped “due to budget constraints attributable to the covid-19 pandemic”) before the planned number of outcomes needed to find a statistically significant difference between the two groups had occurred. So, although they found fewer people in the colchicine group experienced first fatal or non-fatal recurrent ischaemic stroke, myocardial infarction, cardiac arrest, or hospitalisation for unstable angina (9.8% v 11.7%, hazard ratio (HR) 0.84), the study was underpowered with a wide confidence interval (HR 95% CI 0.68 to 1.05).
Lancet doi:10.1016/S0140-6736(24)00968-1
Cutting cardiovascular risk
The easiest way to reduce cardiovascular risk, it seems, is to change the way you calculate it. Recommendations in the US currently use controversial pooled cohort equations (PCEs), which are based on old, non-representative (mainly white people) cohort data. If the newer American Heart Association PREVENT equations were used instead, 17.3 million people in the US who were previously recommended statin therapy for primary prevention would no longer be considered at high enough risk to be eligible. PREVENT removes race from the equation and adds more variables, including estimated glomerular filtration rate (eGFR) and social deprivation. Ten year cardiovascular risk estimates were slashed across the board when comparing PREVENT with PCEs, but by most in Black adults, from an average of 10.9% to 5.1%, and in older people aged 70-75 years, from 22.8% to 10.2%.
JAMA Intern Med doi:10.1001/jamainternmed.2024.1302
A sepsis study with added bling
“BLING III is a beautiful and impressive example of true team science” according to the editorial accompanying it in JAMA. Some 800 study investigators across three continents enrolled 3498 adults with sepsis or septic shock to try to determine whether continuous or intermittent infusions of β-lactam antibiotics are more effective. Continuous infusions make sense as high cardiac output and leaky capillaries tend to increase drug clearance in people with sepsis, but does this translate to long term survival? All-cause mortality within 90 days was lower in the continuous infusion arm of BLING III (24.9% v 26.8%). A systematic review and meta-analysis incorporating the BLING III results (and published at the same time) found a risk ratio for all-cause mortality within 90 days of 0.86 (95% credible interval 0.72 to 0.98) for continuous versus intermittent β-lactam infusions.
JAMA doi:10.1001/jama.2024.9803
No pain, no gain?
“At least I know it’s working” is the stoical response of many people looking for a silver lining to feeling rough for a couple of days after a covid or flu vaccination. An observational study of people having their primary covid-19 vaccination in 2021 backs this theory up, to a point. They found that people who reported chills, tiredness, feeling unwell, or headaches after their second vaccine had a 1.4-1.6 times higher level of neutralising antibodies at 1 and 6 months’ follow-up than those with no symptoms. The authors warn, however, against making inferences about side effects and immunity at an individual level.
Ann Intern Med doi:10.7326/M23-2956
Footnotes
Competing interests: None declared
Provenance and peer review: Not commissioned; not peer reviewed