The World Health Organization (WHO) today announced that it has prequalified a second dengue vaccine, TAK-003, known as Qdenga and developed by Takeda. 

Qdenga is a live-attenuated vaccine that contains weakened versions of all four dengue serotypes. The WHO recommends its use in children ages 6 to 16 years old in settings where the dengue burden and transmission intensity is high. It is given in two doses, 3 months apart.

Prequalification means the WHO has assessed the quality, safety, and efficacy, and the step paves the way for countries and groups to buy the vaccine for a broader rollout. 

Step paves way for broader global access

Rogerio Gaspar, PhD, the WHO's director for regulation and prequalification, said Takeda's dengue vaccine is now eligible for procurement by United Nations agencies, including UNICEF and the Pan American Health Organization (PAHO). "With only two dengue vaccines to date prequalified, we look forward to more vaccine developers coming forward for assessment, so that we can ensure vaccines reach all communities who need it."

Brazil's drug regulators approved Qdenga in 2023, and, earlier this year, the first mass vaccination campaign launched in the city of Dourados in Brazil's Mato Grosso del Sul state.

The other prequalified dengue vaccine is Dengvaxia, made by Sanofi. It is given in a three-dose series, 6 months apart. It requires prevaccine screening and is given only to people who have had a previous dengue infection to avoid antibody-dependent enhancement, a phenomenon that makes repeat infections more severe and can cause severe illness after vaccination in those who haven't previously been exposed to the virus.

An international group of scientists estimates that the mean infection-to-symptom-onset incubation period of the 2022 global mpox outbreak was similar to that of previous outbreaks, but the onset-to-onset serial interval was about 5 days shorter in 2022. The serial interval is the time between when symptoms first appear in an initial patient and in the person he or she infects.

The findings are published in Emerging Infectious Diseases and may suggest that the shift to a predominantly sexually associated mode of transmission in 2022 may have influenced the serial interval, as well as more public health awareness and surveillance during the global outbreak.

Mpox outbreaks recorded since the 1950s have been defined by household transmission patterns and small case counts, but in the 2022 outbreak the virus became predominantly transmitted through sexual encounters between men who have sex with men. 

Shorter onset-to-onset by 1 week

In the study, the authors compared transmission and onset data in 15 studies with a total of 42 case records from pre-2022 mpox outbreaks with data from 42 relevant studies conducted during the 2022 outbreak. 

They found that the incubation period was 8.1 days in 2022 and 8.2 days in previous outbreaks, but the serial interval was 8.7 days in 2022 and 14.2 days in previous years.

Our study highlights the importance of monitoring temporal changes in transmission and disease progression.

The authors conclude, "Because estimated values of epidemiologic parameters are often used to inform interventions against a range of pathogens, our study highlights the importance of monitoring temporal changes in transmission and disease progression."

A single-center analysis published today in Travel Medicine and Infectious Disease finds that 86% of travelers returning to Spain with a chikungunya virus infection during a 2-year period reported joint pain that significantly reduced their quality of life. 

Researchers at La Paz-Carlos III University Hospital in Madrid, Spain, evaluated travelers who visited Latin American countries from April 2014 to September 2016, during outbreaks of the mosquito-borne virus. The median age of the 119 travelers was 41 years, 67.2 were men, and 25.6% had visited a travel clinic before departure.

In the United States, the Food and Drug Administration (FDA) approved Valneva's IXCHIQ chikungunya vaccine for adults in November 2023. In February 2024, the Centers for Disease Control and Prevention's (CDC's) Advisory Committee on Immunization Practices (ACIP) recommended the vaccine for certain travelers to affected world regions and chikungunya lab workers.

The most common symptoms of chikungunya are fever and joint pain, with the pain persisting from a few days to years. In unusual cases, death can result, usually in older people or children younger than 1 year.

Average duration of pain was 4 months

On average, the 102 joint-pain patients (86%) reported pain for 129.4 days. Risk factors for chronic joint pain were female sex, country of infection, older age, more than four symptoms during infection, high viral load, pain in previously injured tendons or joints, and certain lab markers.

Patients with chronic joint pain had to significantly adjust their normal daily activities, and 42.6% reported recurrence of symptoms after they had resolved. These patients said their symptoms improved substantially after they received tailored therapies.

Risk factors for chronic joint pain were female sex, country of infection, older age, more than four symptoms during infection, high viral load, pain in previously injured tendons or joints, and certain lab markers.

"The results of this study underscore the need for: (1) comprehensive pre-travel advice; (2) effective management of patients in specialized units, alongside early diagnosis and treatment, to prevent trivialization of these viral infections; and (3) the development of interdisciplinary recommendations to assist physicians in treating patients and enhancing outcomes," the study authors concluded.