1-dose Jynneos vaccine effectiveness against symptomatic mpox estimated at 78%

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Mpox virusesEstimated vaccine effectiveness (VE) of a single dose of the Jynneos attenuated smallpox/mpox vaccine against symptomatic mpox infection was 78% at least 14 days later, according to a study published yesterday in The Lancet Infectious Diseases.

Researchers at the UK Health Security Agency sent questionnaires to men who have sex with men (MSM) in England diagnosed as having mpox from July 4 to October 9, 2022, and linked the answers to lab data and a public health case-management system.

The team calculated VE by comparing vaccine coverage among eligible patients from the number of estimated doses given to at-risk MSM and the estimated size of that population.

2.2% breakthrough infection rate

By October, 47% of 363 mpox patients had received one dose of the Jynneos vaccine. Eight respondents (2.2%) had breakthrough infections at least 14 days after vaccination, 32 (8.8%) were diagnosed within 13 days after vaccination, and 323 (89.0%) were unvaccinated.

Estimated one-dose VE against symptomatic mpox was 78% after at least 14 days (95% confidence [CI], 54% to 89%), ranging from 71% to 85% in sensitivity analyses. VE was –4% in the first 13 days after vaccination (95% CI, –50% to 29%).

"A single MVA-BN [Jynneos] dose was highly protective against symptomatic mpox disease among at-risk [MSM], making it a useful tool for mpox outbreak control when rapid protection is needed," the authors wrote. "For cases in which numbers at highest risk of infection exceed vaccine supply, there might be benefit in prioritising delivery of first doses."

There might be benefit in prioritising delivery of first doses.

In a related commentary, Dimie Ogina, MBBS, of Niger Delta University in Nigeria, and Nathalie Strub-Wourgaft, MD, of the Drugs for Neglected Diseases Initiative in Switzerland, noted that half of the breakthrough mpox infections occurred in HIV patients.

"However, the MVA-BN vaccines have previously been shown to be immunogenic among adults with a history of AIDS, and larger cohorts of people living with HIV will be required to ascertain if HIV is a risk factor for MVA-BN vaccine failure," they wrote.

Lack of sleep may lower immune response to vaccines

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Flu vaccine vial and syringeLess than 6 hours of sleep a night in the days before and after flu and hepatitis A and B vaccination was associated with a lower immune response, according to a review and meta-analysis published yesterday in Current Biology.

To summarize the evidence regarding the amount of sleep obtained in the days surrounding vaccination and antibody response, an international team of researchers reviewed 165 studies, 7 of which were included in the meta-analysis. The association between self-reported short sleep (less than 6 hours a night) and reduced vaccine response did not reach the researchers' pre-defined statistical significance criteria, but among the studies that objectively measured sleep duration (using wearable activity trackers or measuring sleep in the lab), the analysis found a robust decrease in antibody response (304 participants, ages 18 to 60; overall pooled effect size [ES], 0.79; 95% confidence interval [CI], 0.40 to 1.81).

The pooled ES was large in men (ES, 0.93; 95% CI, 0.54 to 1.33) but did not reach significance in women (ES, 0.42; 95% CI, –0.49 to 1.32).

"The link between sleep and vaccine effectiveness could be a major concern for people with irregular work schedules, especially for shift workers who typically have reduced sleep duration," senior study author and University of Chicago Professor Emeritus of Medicine Eve Van Cauter, PhD, said in a university press release. But she noted that for others it's a modifiable behavior that can be adjusted around the time of the appointment.

The link between sleep and vaccine effectiveness could be a major concern for people with irregular work schedules.

"This is something people should consider planning around, to ensure that they are getting enough sleep in the week before and after their vaccines," she said.

Although the meta-analysis did not include data examining lack of sleep and immune response to COVID-19 vaccines, the researchers estimated that the ES for objectively measured short sleep (0.79) was identical to the estimated ES of the waning of the immune response 2 months after the Pfizer-BioNTech COVID-19 vaccine.

Van Cauter and her colleagues say they hope the results will spur further research into the phenomenon.

Botulism outbreak in Europe linked to weight loss procedure

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The European Centre for Disease Prevention and Control (ECDC) reported today that 67 cases of botulism linked to a weight loss procedure have been reported in Turkey and three other European countries.

The 67 cases of the neuroparalytic illness have all been linked to intragastric injection of the botulism neurotoxin (BoNT), with 53 cases reported in Turkey, 12 in Germany, and 1 each in Austria and Switzerland. The patients had the procedure from February 22 to March 1, and among the 63 patients with information, 60 were treated at a private hospital in Istanbul and 3 at a hospital in Izmir. The relevant departments of both hospitals have had their activities suspended.

Symptoms range from mild to severe, with several of the patients hospitalized and a number reportedly admitted to intensive care units and treated with botulinum anti-toxin.

BoNT products, such as Botox, are derived from the bacterium Clostridium botulinum and are commonly used for cosmetic purposes. The ECDC said investigation by Turkish authorities found that licensed BoNT products were used in the procedures, but that these products are not approved for the treatment of obesity by intragastric injection. Excessive doses of BoNTs can cause botulism.

The ECDC is warning European Union/European Economic Area citizens to avoid intragastric treatments with BoNT for obesity in Turkey.

Brazil green-lights Takeda's dengue vaccine

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Brazil's drug regulatory agency has approved Japan-based Takeda's four-strain vaccine against dengue virus for use in people ages 4 to 60 years old, the company announced yesterday.

Takeda's vaccine can be used regardless of earlier dengue infection and doesn't require testing for prior infection before use. Brazil is the first country in Latin America to approve the vaccine, called Qdenga, to combat the mosquito-borne disease.

The company's vaccine is a live attenuated product built on a serotype 2 backbone and includes all four dengue serotypes. It is given subcutaneously in two doses, 3 months apart.

Brazilian officials based their approval on clinical studies that included more than 28,000 children and adults. Efficacy varied by dengue serotype, and over the 4.5-year study period, the vaccine prevented 84% of hospitalized cases and 61% of symptomatic cases.

Vivian Kiran Lee, MD, Takeda's medical affairs director in Brazil, said dengue outbreaks and hospitalizations strain Brazil's health system. In 2022, the country saw a huge spike in activity, resulting in more than 1.4 million cases and more than 1,000 deaths. She said the company's vaccine reduces barriers to vaccination and has the potential, when combined with vector control programs, to reduce the burden of the disease on health systems.

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