Alex Nowbar reviews the latest research from the top medical journals

Veggie vaccine for flu

Ward and colleagues present the findings of two major randomised controlled trials of their recombinant quadrivalent influenza vaccine manufactured in plants. There is already a vegan (not egg based) vaccine for flu, but this is the first vaccine made by a plant to be tested at scale (thousands of patients). The plant is Nicotiana benthamiana, which, as you might have guessed, is a relative of the tobacco plant. The headline of these efficacy trials is that the vaccine was safe, immunogenic, and effective. The efficacy was broadly similar to existing vaccines, but technically the study in 18-64 year olds in the 2017-18 northern hemisphere flu season showed 35% absolute efficacy when the target was 70%. A plant based platform supposedly has the benefits of rapid production and a reduction in random mutations that can reduce efficacy. The authors’ conclusion that “the extent to which the potential advantages of the plant-derived, virus-like particle vaccines can be realised would only become apparent with broader use over several seasons once the vaccine is approved for human use” is well put.

Lancet doi:10.1016/S0140-6736(20)32014-6

Tales of tallness

Have you ever wondered which country has the tallest people? Probably not. (It’s the Netherlands.) Mean height in countries with the tallest people was 20 cm taller than in countries with the shortest people. It is debatable to say that a country’s population’s height and body mass index are markers of nutrition in that country when genetics also have a huge role to play, but when you add in the trends with age from 5 years to 19 years old, over the time period from 1985 to 2019, it adds weight to the nutrition argument. This detailed, 200-country study noted that children in many countries in sub-Saharan Africa, New Zealand, and the US gained too little height, and too much weight for their height, compared with children in other countries. The overall message was huge heterogeneity between countries, but that health programmes should target children and adolescents in school years to improve healthy growth. We already knew this, but this new study supports and informs the principle by providing specific estimates and patterns.

Lancet doi:10.1016/S0140-6736(20)31859-6

Online weight management tool in diabetes

Baer and colleagues assessed the effect on weight loss at 1 year of an online weight management programme plus population health management compared with the online programme only and with usual care. The study design, a cluster randomised trial, is necessary when the nature of the intervention means it cannot be applied to individuals. In this case the intervention involved a non-clinical staff member acting as a population health manager for US primary care practices. The combined intervention resulted in more weight loss than usual care or than the online programme alone. With a mean weight loss of only 3% in the combined intervention group, this is arguably not clinically significant, but it may still be worth pursuing given that the intervention is relatively low cost and amenable to upscaling.

JAMA doi:10.1001/jama.2020.18977

Safe surveillance strategies?

Outcomes from early prostate cancer may differ between white (non-Hispanic) and black men. Deka and colleagues performed a retrospective cohort study of 8726 men who were under active surveillance for low risk prostate cancer in the US. It showed that black men were more likely to experience disease progression and definitive treatment at 10 years, but there was no difference in incidence of metastasis or prostate cancer-specific mortality. The lack of difference in mortality is surprising, but we can speculate that a higher mortality might have been seen with longer follow-up. These data are observational, so subject to confounding. There is also no comparison between different surveillance strategies. I’m not sure what to take away from this. Knowing certain people have worse outcomes doesn’t tell you what can be done about it. It’s not clear what is mediating the difference.

JAMA doi:10.1001/jama.2020.17020

Lifestyle intervention for people at risk of diabetes

Sampson and colleagues performed a randomised controlled trial of a lifestyle intervention for preventing diabetes in the UK. The intervention involved six core sessions, and up to 15 maintenance sessions, of patient-centred counselling for changes in physical activity and diet. It is described as “low cost,” although I don’t know how that was assessed. It reduced the incidence of type 2 diabetes at two years by 40% in people in a high risk glycaemic category (also known as “pre-diabetes,” although this term has fallen out of favour). Case closed? In short, yes. We should implement this intervention. To some extent, we are already: this trial was started in 2011, when perhaps we weren’t. One notable limitation was that the population studied were mostly white. I don’t think this means the results won’t be generalisable, though.

JAMA Intern Med doi:10.1001/jamainternmed.2020.5938

Alex Nowbar is a clinical research fellow at Imperial College London