London School of Hygiene & Tropical Medicine

MONDAY, Sept. 30, 2024 -- Measles cases in England are consistent with the waning of vaccine-induced immunity, according to a study published online Sept. 26 in The Lancet Public Health . Alexis Robert, Ph.D., from the London School of Hygiene & Tropical Medicine, and colleagues examined whether measles dynamics observed in England between 2010 and 2019 were in line with waning of vaccine-induced immunity using a compartmental mathematical model stratified by age group, region, and vaccine status. The deterministic model was fitted under three scenarios: without waning of vaccine-induced immunity, with waning depending on time since vaccination, and with waning depending on time since vaccination starting in 2000. The researchers found that the number of one-dose recipients among measles cases was overestimated in the scenario without waning, and the number of two-dose recipients was underestimated among cases older than 15 years (median, 75 cases in simulations without waning; 196 cases in simulations with waning; 188 cases in simulations when waning started in 2000; and 202 observed cases). The number of onward transmissions from vaccinated cases was 83 percent of transmissions from unvaccinated cases. There was a slow estimated waning rate (0.039 percent per year of age), but this was sufficient to increase the burden of measles. "The waning of vaccine-induced immunity likely explains the observed dynamics and age distribution of vaccinated measles cases in England between 2010 and 2019," the authors write. "Many near-elimination countries have reported decreased vaccine coverage since 2020, leading to an increase in measles incidence in Europe in 2023." Abstract/Full Text Whatever your topic of interest, subscribe to our newsletters to get the best of Drugs.com in your inbox.

A new study did not link Novo Nordisk's older GLP-1 med liraglutide to suicidal ideation. Regulators in both the U.S. and Europe have looked into the potential link between suicidal thoughts and Novo Nordisk’s blockbuster semaglutide franchise after reports sounded the alarm last year. While the agencies found no increased risk for the popular diabetes and obesity drug, a new study could fuel the debate.In a study recently published in the Journal of the American Medical Association (JAMA), researchers found a “significant disproportionality” for semaglutide-associated suicidal ideation compared with other medicines, particularly among patients who also use antidepressants. No such link was found for Novo’s earlier-generation GLP-1 med, liraglutide, according to the team. The study was based on the World Health Organization's (WHO's) database of suspected suicidal and self-injurious adverse drug reactions. Branded as Wegovy, Ozempic and Rybelsus, Novo’s semaglutide medicines—and their liraglutide counterparts Victoza and Saxenda—all fall under the GLP-1 umbrella. The drug class has seen soaring popularity in recent years as its list of documented benefits has expanded, bringing on an onslaught of new patients. The JAMA study notably includes patients who potentially used the GLP-1 meds off-label, and the data also lacked other information that could potentially play a part in added mental distress, such as rapid changes of body weight or BMI.More importantly, a higher rate of suicidal ideation does not mean a causal relationship. In a series of reactions disseminated by Science Media Centre, an independent science information organization, several experts called into question the significance of the research. Multiple experts said the study's method of finding a statistical disproportionality between two groups does not prove causality."Signal detection studies in pharmacovigilance databases are good for generating hypotheses, but are not suitable for assessing whether there is a causal association between a drug and an outcome," Ian Douglas, professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine, said in a statement.Novo, for its part, flagged “several limitations” of the study and maintained that it will continue to work with the FDA and other regulators to monitor the safety of its GLP-1 products, a company representative said in an emailed statement.“We stand behind the safety and efficacy of all of our GLP-1RA medicines when they are used as indicated and when taken under the care of a licensed healthcare professional,” the spokesperson said. “The known risks associated with use of these medicines are reflected in their current FDA- and EMA-approved product labeling.”Last year, two cases of suicidal thoughts and one case of self-harm from patients in Iceland prompted an investigation from the European Medicines Agency (EMA). And 201 reports of suicidal thoughts received by the FDA from users of semaglutide or Eli Lilly’s rival tirzepatide sparked a U.S. probe. While both regulators are still monitoring reports and probing any potential link, neither has so far found evidence that these medicines causes suicidal thoughts or actions. Still, the JAMA study authors assert that a “precaution of use” in patients with psychiatric disorders or psychological lability could be added to the semaglutide package insert. The FDA label on Novo’s Wegovy already includes a similar warning, the researchers pointed out.Other studies, such as one published in the journal Nature Medicine, have backed the FDA and EMA’s conclusions. The Nature Medicine study found that in 1.8 million diabetes and obesity patients, those who used semaglutide were less likely to have suicidal thoughts than patients on other treatments. The findings from the EMA, FDA and other independent researchers align with Novo’s trial data, “including large-scale outcomes trials and observational studies,” according to the company spokesperson. 

Bavarian Nordic’s mpox vaccine is currently only indicated for adults 18 years and older. Image credit: Shutterstock/ Riccardo Mayer. Amid the ongoing global mpox public health emergency, Bavarian Nordic – manufacturer of the only approved vaccine for the disease – has submitted data to the European Medicines Agency (EMA) to support an extension for its use in teenagers. If approved by the EMA, the marketing authorisation extension would grant use of the Imvanex (MVA-BN) vaccine in adolescents from 12 to 17 years of age. Bavarian Nordic stated the change could happen in Q4 2024, according to a 16 August press release. The news comes on the same day as Sweden reported its first confirmed case of mpox arising from a more serious variant. This is the first the more contagious version has been found outside Africa. The data submitted to the agency is from an interim analysis of a clinical study (NCT05740982) sponsored by the US National Institutes of Health (NIH). The Phase II trial, which involved 315 adolescents, demonstrated the vaccine worked with the same efficacy and safety as in adults. The Imvanex vaccine is currently only indicated for adults 18 years and older though it can be used in adolescents in the US, where it is known under the brand name Jynneos, owing to a US Food and Drug Administration (FDA) emergency use authorisation. See Also: Licensing agreements for innovator GLP1R drugs weigh in with over $6.2bn in 2024 Top 20 biopharmas’ market cap up 4.3% in Q2 2024 as GLP-1 drug innovators hold top spots The Danish company said it is also preparing trials studying the vaccine’s use in children from 2 to 12 years of age. The trial, partially funded by the Coalition for Epidemic Preparedness Innovations (CEPI), is expected to start in the Democratic Republic of Congo and Uganda later this year. Bavarian Nordic said this could also potentially support a regulatory approval of Imvanex for that age group in African countries. Current mpox health emergency Earlier this week, Africa Centres for Disease Control and Prevention (CDC) declared a public health emergency amid mpox outbreaks in its member states. This was swiftly followed by the World Health Organization (WHO) declaring a public health emergency of international concern. Whilst mpox cases have steadily increased in areas of Africa over the past decade, the number of cases reported so far this year has already exceeded last year’s total, with more than 15,600 cases and 537 deaths. Bavarian Nordic said it would donate 40,000 doses of its vaccine to the agency to combat the disease, along with an order of 175,420 doses commissioned by the European Health Emergency Preparedness and Response Authority (Hera). Africa CDC’s Director-General Dr. Jean Kaseya has stated the agency plans to secure around ten million doses to curb the disease outbreak this year. Michael Marks, professor of Medicine at the London School of Hygiene & Tropical Medicine (LSHTM), said in a statement: “We need a large supply of vaccine so that we can vaccinate those most at risk – in the current outbreak that might be sex workers, children and adults living in areas with many cases. “The best available evidence supports a need for pre-exposure vaccination, where people at risk are vaccinated before they come into contact with a case. There is less strong evidence in support of post-exposure vaccination.” Vaccine bottlenecks Shares in Bavarian Nordic have soared since the outbreak, opening 24.8% higher on 16 August compared to the beginning of the week [12 August] before the agencies declared public health emergencies. Bavarian Nordic’s market cap is $22.4bn. Imvanex generated sales of $730m in 2023, nearly thrice as much as in 2022, with vaccine revenue now expected to skyrocket in the remainder of 2024. GlobalData’s associate director of infectious diseases Fiona Chisholm said: “Bavarian Nordic has confirmed that it has the capabilities to produce 10 million doses of the vaccine by the end of 2025 and is waiting to receive orders. “Nonetheless, vaccines will remain in extremely short supply across countries currently dealing with soaring cases, at least in the short term. This highlights the need for a coordinated international response that ramps up pressure on countries with stockpiles to donate their mpox vaccines.”