By Chris Berrie
LJUBLJANA, Slovenia -- May 13, 2019 -- Premature infants experience a high proportion of immune responses -- similar to those of full-term infants -- with the hexavalent vaccine against diphtheria, tetanus, pertussis, hepatitis B, poliomyelitis and invasive diseases caused by Haemophilus influenzae type b (DTaP-IPV-Hib-HepB; Vaxelis™), according to results of a meta-analysis presented here on May 9 at the 37th Annual Meeting of the European Society for Paediatric Infectious Diseases (ESPID2019)
The vaccine also has an acceptable safety profile with this fragile population.
Immunogenicity and safety of the hexavalent DTaP-IPV-Hib-HepB vaccine has been evaluated in various phase 2/3 randomised clinical trials that have included over 6,800 children. Marissa B. Wilck, MBChB, Research, Merck & Co. Inc., Kenilworth, New Jersey and colleagues integrated and analysed data from 6 such studies, identifying 159 premature infants using the terms “premature baby/delivery” and/or “low birth-weight baby.” The investigators then collected and summarised immunogenicity and safety data by patient and treatment group.
A total of 49 premature infants were in the control-vaccine groups (European trials: DTaP3-IPV-HepB/Hib [Infanrix™]; North American trials: DTaP5-IPV/Hib [Pentacel™]) and 110 were in the DTaP-IPV-Hib-HepB vaccine group.
“These studies were done in different countries, with different schedules, and with different concomitant vaccines,” noted Dr. Wilck. Across these trials, however, high percentages of premature infants mounted protective protocol-defined responses to these antigens -- in particular, against pertussis. They also achieved early and sustained H. influenzae type b responses, which persisted through the first year of life.
The researchers determined proportions of these premature infants showing immune responses following the specific infant immunisation series according to the individual antigens, against diphtheria, tetanus, pertussis (pertussis toxoid [PT], filamentous haemagglutinin adhesin [FHA], pertactin [PRN], fimbriae 2/3 [FIM2/3]), hepatitis B (surface antigen [HBsAg]), poliomyelitis (types 1, 2, 3) and H. influenzae type b (polyribosylribitol phosphate [PRP]).
In the safety analysis, within the premature population across the control and DTaP-IPV-Hib-HepB vaccination groups, the investigators observed similar rates for early solicited injection site (76% vs 76%), and both systemic (84% vs 95%) adverse events (days 1 to 5) and unsolicited systemic adverse events (days 1 to 15; 35% vs 42%). There were few serious adverse events (days 1 to 15; 4% vs 2%).
The researchers observed similar results for DTaP-IPV-Hib-HepB vaccination comparisons between the premature and overall trial populations for early solicited injection site (76% vs 85%) and systemic (95% vs 94%) adverse events (days 1 to 5), and unsolicited systemic adverse events (days 1 to 15; 42% vs 52%). Again, there were few serious adverse events (days 1 to 15; 2% vs 1%).
There was only 1 discontinuation due to adverse events across the full population of premature infants.
“We have good safety signals and what looks like a good immune response [for these premature infants] in this particular integration of these studies,” Dr. Wilck concluded.
Funding for this study was provided by Merck & Co., Kenilworth, New Jersey.
[Presentation title: Safety and Immunogenicity of Vaxelis™ in Premature Infants. Session EPD12]
To read more Conference Dispatch articles, click here.