Mexican Scientists Successfully Develop Chikungunya Vaccine

IPN scientists, in collaboration with the universities of Oxford and Texas, successfully concluded the first human trials of a vaccine to prevent Chikungunya virus infection (CHIKV), transmitted by Aedes mosquitoes.

The vaccine is based on the adenovirus ChAdOx1, which has been used by Oxford and AstraZeneca as a vaccine platform for COVID-19, explained in a press release Arturo Reyes-Sandoval, Director General of IPN. He added that the ChAdOx1 Chik injection was given to 24 healthy volunteers between the ages of 18 and 51, a common range used in phase 1 clinical trials in which a vaccine is administered to people for the first time.

The results indicated that 100 percent of the volunteers who received the vaccine showed seroconversion, or the presence of antibodies against CHIKV regardless of the dose used, which allowed researchers to foresee that even very low doses would allow high levels of protection against CHIKV.

Since its emergence in Tanzania in 1952, and subsequent reemergence in a series of outbreaks in Kenya, the Indian Ocean (2004–2006) and the Americas (2013–2017), CHIKV has become a major international health concern, with both acute and long-term impacts on public health. CHIKV has been identified in over 100 countries across Africa, Asia, Europe and the Americas.

With no vaccine for prevention nor medicine for treatment, “most people infected with CHIKV will develop symptoms,” according to CDC. The most common symptoms are fever and joint pain, besides headache, muscle pains and joint swelling. While most patients usually feel better within a week, newborns and older adults are at risk for more severe disease.

The scientists also measured the ability of the serum to neutralize CHIKV in vaccinated people through tests that quantify the serum's ability to prevent the virus from penetrating its target cell. The results indicated that even the lowest doses of the vaccine administered once induced high levels of neutralization of CHIKV in 100 percent of the volunteers from day 14 after vaccination and remained high during the six months that the clinical trial lasted.

Reyes-Sandoval has worked on chimpanzee adenovirus vaccines, such as ChAdOx for years. “My goal has been to work on diseases that are present in Mexico, Latin America, Brazil, because of my background, because they are not being explored, and because I thought I could make a difference in those diseases,” said to The Telegraph Reyes-Sandoval. 

IPN scientists have funding from the federal government to start the laboratory and continue with further trials in Mexico, said Reyes-Sandoval, whose work could impact in millions of people in developing countries.