November 11, 2018

Research Roundup: Chikungunya vaccine trial, Ebola vaccine technology, and Zika biomarkers could lead to prenatal diagnostic

Ansley Kahn
Senior Program Assistant
PATH/Satvir Malhotra

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After hitting its primary goal in a phase 2 trial, Themis may be one step closer to developing a vaccine to protect against chikungunya—a disease which causes debilitating joint pain and for which there is currently no treatments or vaccines. MV-CHIK, Themis’ chikungunya vaccine candidate, was tested at two dose levels in a total of 263 participants and was found to induce neutralizing antibodies against the disease in all groups after two injections. Themis reported seroconversion rates ranging from 86 to 100 percent, touting the vaccine candidate as “promising and potentially effective” against the disease. Themis is looking to move the vaccine candidate into a phase 3 study “in the near term” and will likely pursue a priority review voucher, as the US Food and Drug Administration recently added chikungunya to its list of eligible diseases. 

A new study suggests that frontline health workers in the Democratic Republic of Congo who received experimental Ebola vaccines could be protected against the virus for longer than a year. The study, which tracked healthy volunteers in the United Kingdom who received vaccines against Ebola between 2014-2016—including Merck’s rVSV-ZEBOV, GlaxoSmithKline’s ChAd3 EBOV, and Janssen’s AdHu26—found that after two-and-a-half years, those vaccinated still have a strong antibody response to the virus. These findings provide insight into how the vaccines can be used in future outbreaks in the region and how health care workers could be vaccinated before the disease becomes widespread during an outbreak. Researchers now plan to give a booster dose to the study participants to determine how it adds to their immunity. By utilizing the same technology used to develop the Ebola vaccine—a technology known as viral vectors—researchers also believe they can speed the development of vaccines for other infectious diseases.

Researchers at the University of Southern California believe they have identified a panel of biomarkers specifically associated with symptomatic Zika infection during pregnancy—a discovery which could lead to the development of new prenatal screening tests to detect fetal abnormalities caused by the virus, as well as a better understanding of how Zika causes these abnormalities. During the study, researchers examined the immune systems of pregnant women through blood samples—comparing the samples of 30 Zika-infected pregnant women in Brazil to 30 healthy pregnant women in Brazil and 14 in Los Angeles. The researchers specifically examined cytokines, messenger chemicals released by the body in response to an infection, and identified 16 cytokines associated with abnormal births from Zika. However, it is unclear if the cytokines cause the birth abnormalities or are released in response to another cause.