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PCV13 protects against S. pneumoniae in term, preterm infants
Most term and preterm infants had adequate protection against Streptococcus pneumoniae following a 13-valent pneumococcal conjugate vaccine series, according to a recent study.
“Immune responses were lower in preterm infants than in term infants,” Federico Martinón-Torres, MD, PhD, from the Hospital Clínico Universitario de Santiago de Compostela in Spain, and colleagues wrote. “However, the majority of subjects in both groups achieved both pneumococcal serotype-specific IgG antibody levels after the infant series that exceeded the World Health Organization-established threshold of protection and functional antibody responses.”
The phase 4, open-label, 2-arm trial assessed the safety and efficacy of PCV13 (Prevnar 13, Wyeth Pharmaceuticals) in 100 term and 100 preterm infants. The patients received a series of PCV13 at 2, 3, and 4 months and a toddler dose at 12 months. The vaccine was administered in addition to other routine vaccines, including diptheria-tetanus-ascellular pertussis, hepatitis B, inactivated poliovirus and Haemophilus influenzae type b vaccine and meningococcal group C conjugate vaccine.
More than 85% of patients attained or exceeded the WHO’s threshold for anticapsular immunoglobulin G (IgG) antibody concentration (≥0.35 µg/mL) one month following the infant series, except for preterm patients who had 5, 6A and 6B serotypes.
The immune response rates increased to more than 97% a month after the toddler dose among all patients and serotypes except for serotype 3. Researchers reported that the results were correlated with a booster response following the administration of toddler dose.
“Responses were uniformly higher after [toddler dose], reinforcing the importance of a timely booster dose,” they wrote.
Opsonophagocytic activity also increased after the toddler dose and toddler dose vaccine in all patients, even those with serotype 3, according to the results. Preterm patients with genotypes 4, 18C, 1, 5, 6A and 19A had the least activity.
A subgroup analysis of preterm patients categorized by gestational age (32 - <37 completed weeks, 29 - <32 weeks and <29 weeks) demonstrated parallel outcomes, but patients in the highest gestational age group exhibited higher IgG antibody concentrations.
Overall, patients had similar reactions to the vaccine and less than 10% experienced a severe reaction. The most common serious adverse events were respiratory and gastrointestinal infections, most of which occurred following the infant vaccine series among preterm patients (14% vs. 5%; P = 0.051).
“PCV13 was generally well tolerated in the preterm infants when administered on an accelerated schedule, and the observed [adverse events] were consistent with childhood illnesses common in this population,” the researchers concluded. “These results reinforce the importance of timely pneumococcal vaccinations for all infants, including those born prematurely.”
Disclosure: Federico Martinón-Torres, MD, PhD reports research grants and/or honoraria as a consultant/advisor and/or speaker from GlaxoSmithKline, Sanofi Pasteur MSD, Sanofi Pasteur, Pfizer Inc/Wyeth, Novartis and MedImmune Inc. See the study for a full list of financial disclosures.
