Nova vacina contra dengue, imunogênica ou protetora?

Manoel Barral

A Business Week anunciou hoje os resultados da publicação do JID A Novel Tetravalent Dengue Vaccine Is Well Tolerated and Immunogenic against All 4 Serotypes in Flavivirus‐Naive Adults (publicada no dia 09.01.2010) que mostram que a Sanofi-Aventis, desenvolveu uma vacina efetiva contra dengue.

A publicação diz que a vacina é imunogênica, veja o :

1. “Background.

   

    Sanofi Pasteur has developed a tetravalent dengue vaccine (TDV) against the world’s most common arbovirus infection.
   
2. Methods.

   

    We assessed the safety and immunogenicity of the TDV in healthy adults randomized into 2 groups. Group 1 received 3 TDV injections at months 0, 4, and 12–15; group 2 received saline placebo at month 0 and then 2 TDV injections at months 4 and 12–15. Adverse events were recorded, and biological parameters and viremia levels were measured. Neutralizing antibodies against 4 World Health Organization (WHO) reference strains were measured before and after vaccinations.
   
3. Results.

   

    A total of 33 participants were enrolled in each group. Demographic characteristics were comparable. No vaccine‐related serious adverse event was reported. The most common systemic reactions were headache, malaise, and myalgia. Low viremia levels were detected, mainly of serotype 4. Immune response increased with successive vaccine doses. All participants seroconverted against all 4 serotypes after receiving 3 doses at 0, 4, and 12–15‐months, and almost all seroconverted after 2 doses given 8–11 months apart.
   
4. Conclusions.

   

    Sanofi Pasteur’s TDV was well tolerated and induced full seroconversion against all WHO reference strain serotypes after 3 doses.”
   

Já a notícia na Business Week diz que a vacina protegeu voluntários contra os quatro sorotipos.

1. “Sanofi’s Vaccine for Mosquito Virus Protects Adults, Study Says
   
2. January 11, 2010, 05:15 AM EST
   
3. By Simeon Bennett
   
4. Jan. 11 (Bloomberg) -- Sanofi-Aventis SA’s experimental vaccine against dengue protected healthy volunteers against all four strains of the virus in a study, bringing the drugmaker closer to providing the first vaccine against a disease that threatens 40 percent of the world’s population.
   
5. The vaccine protected all 66 adults a U.S. study in which they were given three shots over 15 months, according to the results published Jan. 9 on the Journal of Infectious Diseases Web site. Most people were protected after two doses, including those who received a placebo for the first injection and the vaccine for the second and third shots, the study showed.”
   

A notícia científica é promissora mas não evidencia proteção. O estudo mostra segurança e imunogenicidade, se situando numa fase I/II. Já a notícia da imprensa fala em proteção, o que não  testado ainda, ou melhor se testado, não foi divulgado neste estudo. Provavelmente não foi testado, e necessitará de um estudo de fase III.

Aliás a própria notícia da BW mostra que os estudos de Fase III devem começar, ou começaram:

1. “Sanofi is conducting a larger trial that includes children, who are more likely to become sick or die from dengue.“
   
2. 
   

Não podemos esquecer que uma notícia deste tipo tem grande implicações econômicas:

1. “Paris- based Sanofi said in May it will invest 350 million euros ($508 million) to build a plant to make dengue vaccine in France, preparing for demand that analysts have said could generate annual market revenue of about $1 billion.”
   

Esta “pressa” da imprensa poderá resultar em valorização das ações da Sanofi-Aventis e já ajudar a custear o próximo estudo....

Desta maneira, a notícia pode se classificar também na categoria Como não dar uma notícia científica.

Ilustração.