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Vaccine for pregnant women against Zika virus is being developed by Butantan

The Butantan Institute is developing a vaccine against Zika for pregnant women – in case of infection, the virus can cause microcephaly in babies. The immunizer is composed of the inactivated virus, an ideal and safer platform for application to pregnant women.

Proof-of-concept studies carried out on animals, to assess the viability of the product, have already shown that the vaccine is capable of generating neutralizing antibodies against Zika.

The next step, scheduled for August 2024, is to carry out pre-clinical safety tests to verify tolerability and possible adverse reactions.

“We have the initial prototype of the vaccine that can be produced under conditions of Good Manufacturing Practices [BPF]. We are working on refining the formulation to move towards pre-clinical trials”, explains the director of the Multipurpose Laboratory, Renato Mancini Astray, one of those responsible for the project.

Despite still being in the initial phase, expectations regarding the new vaccine candidate are positive. It uses classic production techniques, in addition to a traditional adjuvant, aluminum hydroxide (a compound responsible for enhancing the response and helping to maintain it in the long term). These are known methods and considered safe by the scientific community.

“As the main target audience would be pregnant women, the Zika vaccine needs to have a very high safety profile. The reliability of these processes is great, both in scientific terms and in regulatory terms”, points out the researcher.

Researchers have been dedicated to studying the vaccine since 2015, when Brazil faced an epidemic of the virus. Between 2015 and 2022, Brazil recorded around 1,900 cases of this congenital malformation, according to the Ministry of Health.

See also: Federal government predicts increase in dengue cases for the beginning of 2024

Vaccine formulation

Cells are grown in flasks, multiplied in a bioreactor and inoculated with the virus; then, the material is filtered to eliminate cellular contaminants. The next step is to inactivate the virus, using a classic chemical reagent, and then purification takes place. Finally, the inactivated and purified virus is concentrated and formulated. The final product can be stored in common refrigeration (2°C to 8°C).

To arrive at two suitable formulations, more than 60 different compositions were tested in recent years. At this moment, researchers are working on the final version that will be sent for pre-clinical studies.

With the formulation established for now, the product has 100% stability for at least four months and proven activity for up to 8 months. The final composition involves the addition of the adjuvant before filling into vaccine vials, a step that tends to further improve the product’s stability profile.

It is worth noting that, without the virus in circulation, it is not possible to carry out clinical efficacy trials (phase 3) to assess whether vaccinated people become less sick than unvaccinated people – another reason why the study is in an early stage.

Today, there are two immunizers against Zika from foreign pharmaceutical companies being studied in patients, which are in phases 1 (of safety analysis) and 2 (of immunogenicity analysis, that is, ability to induce antibodies) of clinical trials.

(Published by Marina Toledo)

Source: CNN Brasil

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