February 11, 2018

Research Roundup: Two malaria drugs power to limit transmission and the latest on chikungunya and cholera vaccines

Program Assistant
PATH/Gena Morgan

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In this regular feature on Breakthroughs, we highlight some of the most interesting reads in global health research from the past week.

An old malaria compound—primaquine—and a common dye with antimalarial properties—methylene blue—have shown effectiveness in preventing malaria transmission, according to a new study published in The Lancet Infectious Diseases. Researchers found that by adding a single dose of primaquine and three doses of methylene blue to existing malaria medicines, it resulted in near complete cessation of human-to-mosquito transmission within two days. When infected with malaria-causing parasites via mosquito bite, a host may transmit the parasite back to mosquitos, which will likely cause future infection of a different host. These two compounds may aid in preventing this transmission and help curb future malaria infections.

Public health experts recently met to review the latest data on chikungunya vaccine candidates and plan how to promote progress to get the candidates to market. Currently, there are 23 chikungunya vaccine candidates in the pipeline, with two vaccine candidates in phase 2 clinical trials. Researchers discussed the challenges facing developing an effective chikungunya vaccine, citing the unpredictability of where the next chikungunya outbreak could take place. Because of this, phase 3 clinical trials could prove difficult to conduct, unless the trials are conducted in non-human primates injected with human antibodies. Though more research and clinical trials are needed to bring an effective and safe chikungunya vaccine to market, experts believe these conversations will help.

Recent data from Médecins Sans Frontières (MSF) suggests one dose of the oral cholera vaccine is effective in delivering short-term protection against the disease. Previous research from MSF suggested the single dose cholera vaccine provides protection for those with recent exposure to the disease, but the new data—collected from the 2016 cholera outbreak in Zambia—also suggests the vaccine provides protection to those ho have not been exposed to cholera for several years. While this data further demostrates the effectivesness of the single-dose oral cholera vaccine, more research—like the effectivness of the vaccine on children under five years of age—still must be determined.