[SÃO PAULO] On November 9, the United States Food and Drug Regulatory Agency (FDA) approved the first vaccine against the virus that causes chikungunya, a disease that has reported at least 5 million cases in the last 15 years.
The vaccine, called Ixchiq, was developed by the Franco-Austrian biotechnology company Valneva and is initially indicated for people over 18 years of age and at higher risk of exposure to the pathogen.
Ixchiq — which is given as a single dose by injection into the muscle — contains a live, but attenuated, version of the virus and can cause symptoms similar to those experienced by people with the real disease.
In the initial stages of its study in 2018, the vaccine managed to generate antibodies in 100 percent of immunized people, without causing serious adverse events.
“The vaccine also promotes lifelong immunization, so it has the potential to significantly reduce the number of infections to the point of eradicating them.”
William Marciel de Souza, virologist at the University of Texas, USA.
The immunization also presented good results in phase 3 trials carried out in the US between September 2020 and April 2021 with 4,128 volunteers over 18 years of age.
It has been observed to induce the production of neutralizing antibodies in 96.3% of participants six months after application, according to a study published in the journal The Lancet.
“This indicator is important because the US is not an endemic region for chikungunya,” says virologist William Marciel de Souza of the University of Texas. “It’s really excellent news,” because the trend is that antibody production is even higher where the disease is endemic.
The FDA required Valneva to conduct a post-marketing (Phase 4) study to evaluate the risk of serious chikungunya-like adverse reactions after administration of Ixchiq.
Palmira Ventosilla, a specialist in infectious and tropical diseases at the Universidad Peruana Cayetano Heredia, in Peru, points out that the vaccine is an important development, but “additional tests are still necessary to verify its effects on pregnant women or people with comorbidities.”
An emerging threat to global health
Although rarely fatal, the chikungunya virus causes long-lasting, debilitating joint pain in up to 40 percent of the people it infects, most of whom live in hot climates with large mosquito populations. Temples of the Egyptians y Aedes albopictuswhose females transmit the virus.
In the US, almost all cases have occurred in travelers returning from affected countries. For this reason, at the end of October, a working group that advises the Centers for Disease Control and Prevention (CDC) recommended that the vaccine be applied in principle to tourists who will visit countries with active outbreaks or where the disease is endemic.
Individuals over the age of 65 or pre-existing medical conditions that could make them more susceptible to severe illness also “may be considered” if they visit a country that has had an outbreak in the past five years.
The same applies to people who remain in endemic countries for at least 6 months and laboratory workers to manipulate the virus as part of their research.
There is much expectation that FDA approval will help make the vaccine available in other countries soon.
More than 100 countries have already reported local transmission of the virus, including Brazil, which recorded its first case of chikungunya in 2014. Since then, the pathogen has produced at least seven major outbreaks—one per year since 2016—with nearly 254,000. confirmed infections and 1.2 million suspected cases, in addition to a thousand deaths.
“A vaccine with such effectiveness, and if extended to the entire population, could interrupt the transmission of chikungunya in Brazil,” he tells SciDev.Net André Ribas de Freitas, doctor of the Health Surveillance Coordination of the Municipal Health Secretariat of Campinas, in Brazil.
The chikungunya virus leads to the development of long-lasting immunity, so an individual who is cured of the infection would be protected for years, or even life. “The vaccine also promotes lifelong immunization, so it has the potential to significantly reduce the number of infections to the point of eradicating it,” says Souza.
The incorporation of this technology in Latin America and the Caribbean will be done through a collaboration between Valneva and the Butantan Institutein São Paulo, which in 2022 began a phase 3 clinical study to evaluate the safety and effectiveness of the vaccine in 750 adolescent participants between 12 and 17 years old in six Brazilian municipalities where chikungunya is endemic.
The expectation is that Valneva will transfer the technology to Butantan, which will manufacture and distribute the vaccine for Brazil and other low- and middle-income countries affected by the disease. “This is a great gain for Brazil, which is increasingly becoming a hub for the production of immunobiologicals for tropical diseases,” says Freitas.
This article was produced by the Latin America and Caribbean edition of SciDev.Net
2023-11-23 06:53:18
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