Maternal immunization with pneumococcal polysaccharide vaccine in the Philippines

Area of Science:

• Immunology
• Vaccinology
• Maternal and Child Health

Background:

• Pneumococcal disease poses a significant risk to infants.
• Maternal vaccination is a strategy to protect newborns before they can be vaccinated.
• The immunogenicity and transplacental transfer of pneumococcal antibodies in pregnant women require further evaluation.

Purpose of the Study:

• To assess the immune response (immunogenicity) and side effects (reactogenicity) of the 23-valent pneumococcal polysaccharide (Pnc PS) vaccine in pregnant women.
• To determine if antibodies against pneumococcal serotypes transfer from vaccinated mothers to their infants.
• To evaluate the safety and efficacy of maternal pneumococcal vaccination.

Main Methods:

• A randomized controlled trial involving 160 pregnant women.
• Participants received either the Pnc PS vaccine with Haemophilus influenzae type b conjugate vaccine and tetanus toxoid (TT), or TT alone (control).
• Sera and cord blood samples were analyzed for anti-Pnc antibodies using enzyme immunoassay.

Main Results:

• Maternal vaccination with Pnc PS vaccine induced a significant increase in anti-Pnc antibodies (3.3- to 9.1-fold rise).
• Antibody levels in cord blood were significantly higher in the Pnc PS vaccine group compared to the control group.
• Adverse reactions to the vaccine were mild and did not require treatment.

Conclusions:

• The 23-valent pneumococcal polysaccharide vaccine is immunogenic and well-tolerated in pregnant women.
• Maternal vaccination leads to the transfer of protective anti-Pnc antibodies to infants through the placenta.
• Maternal immunization with the Pnc PS vaccine offers a viable strategy for protecting infants against pneumococcal infections.