Vacinar mulheres antes da gravidez contra o Haemophilus influenzae tipo b (Hib), garante recem nascidos com altos níveis de anticorpos contra o patógeno, resolvendo um grande problema da suscetibilidade nos 2 primeiros meses de vida, já que a vacina para o RN só tem indicação a partir da sexta semana.
Trabalho realizado pelo Dr Mathuram Santosham e equipe do John Hopkins in Baltimore e publicado em Novembro último.
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Jaime Nonato Belém/PA
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WESTPORT, CT (Reuters Health) Nov 19 - Infants of mothers immunized =
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against Haemophilus influenzae type b (Hib) with conjugate vaccine =
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before pregnancy show elevated levels of antibody to the pathogen.
Dr. Mathuram Santosham of Johns Hopkins School of Hygiene and Public Health in Baltimore and colleagues point out that there are a number of ways to prevent early neonatal diseases. These include neonatal immunization and immunization of the mother during pregnancy. Another route is pre-pregnancy immunization.
To investigate the effectiveness of this method, the researchers studied 519 healthy non-pregnant Pima Indian women ages 18 to 40 years. They were randomized to receive one of two Hib conjugate vaccines or a 23-valent pneumococcal polysaccharide vaccine. The Hib vaccines were based on oligosaccharides (HbOC) or on polysaccharides coupled to meningococcal outer membrane protein complex (Hib-OMP).
The women who received pneumococcal vaccination served as controls for antibody responses detected in those given Hib conjugate vaccination. The converse was true of those given Hib vaccination, the researchers note in the October issue of the Pediatric Infectious Disease Journal.
Throughout the 37-month observation period, antibody titers were significantly higher in those receiving the conjugate vaccines. Furthermore, the HbOC variety prompted significantly greater responses than the Hib-OMP.
Of the 199 women who gave birth after receiving one or more doses of vaccine, 66 were given HbOC, 70 received Hib-OMP and 63 had the pneumococcal vaccine. All the infants were born "live and healthy," and went on to receive intramuscular Hib-OMP vaccination at 2, 4, and 12 months of age.
The researchers also note that, at birth and at 2 months of age, pre-pregnancy Hib conjugate vaccination of mothers significantly increased the proportion of infants who had protective Hib antibody levels.
In contrast, the investigators point out, infants of mothers given pneumococcal vaccine had antibody titers "similar to those of infants born to mothers who did not receive pneumococcal vaccine before pregnancy."
The findings, Dr. Santosham told Reuters Health, "suggest that vaccinating young women prior to pregnancy has the potential to prevent Hib disease in the first few weeks of life. The currently available vaccines are recommended for use after 6 weeks of age." Therefore, early infections "cannot be prevented with the current strategy."
Immunizing women prior to pregnancy, he added, "has the advantage of providing protection without the concerns about pregnancy complications."
Pediatr Infect Dis J 2001;20:931-940.
