Maternal Vaccination Cuts Newborn Deaths from Lethal Klebsiella Pneumoniae Infections
The research, led by David A. Rosen, an associate professor of Pediatrics and Molecular Microbiology, demonstrated that maternal immunization transferred protective antibodies to newborns, shielding them from lethal infections.
Protecting Against a Deadly Pathogen
Klebsiella pneumoniae is a bacterium particularly dangerous in low‑income countries, where antibiotic‑resistant strains are increasingly prevalent. The pathogen is a major cause of neonatal sepsis, a life‑threatening blood infection. Without an approved vaccine, healthcare professionals face limited treatment options, exacerbating the crisis. The problem is worsened by the rapid increase of strains resistant to usual antibiotics, leaving healthcare professionals with a reduced margin of maneuver and no authorized vaccine to prevent the disease.
Vaccine Efficacy in Mouse Model
The research team developed a mouse model to simulate neonatal sepsis. Pregnant rats received vaccinations targeting the K1 and K2 serotypes of Klebsiella pneumoniae, the most virulent strains. Offspring from vaccinated mothers showed over 80 % survival rates when exposed to lethal bacterial doses two weeks after birth, compared to near‑zero survival in unvaccinated controls. In the control group formed by offspring of non-immunized mothers, survival was null against the K1 strain and less than 35 % against the K2 strain.
The vaccine, created by biotech firm Omniose, was administered during pregnancy, with additional doses given during gestation. The study found that the number of maternal doses (two or three) did not affect the protection level in offspring, suggesting a strong immune response.
Dual Layer of Protection for Newborns
Serological tests revealed that newborns inherited antibodies via both the placenta and breast milk, creating a dual layer of passive immunity. Paeton Wantuch, a researcher at the University of Washington and the study’s first author, emphasized that “mice never directly immunized were highly protected due to antibodies from their mothers.”
The serological follow-up of the offspring, performed weekly from birth to six weeks of life, revealed a constant presence of specific antibodies in the blood of the offspring, as well as in the breast milk collected during the lactation period.
Global Impact and Future Directions
Neonatal sepsis claims thousands of lives annually, particularly in regions with limited healthcare access.
The study’s findings underscore the potential of maternal immunization as a preventive strategy. The team now aims to develop broader‑spectrum vaccines targeting additional Klebsiella strains, with plans to advance toward the first human clinical trials. The final goal is to consolidate the safety of the preparation and move towards the first clinical trials in humans to reduce neonatal mortality on a global scale.
Rosen, associate professor of Pediatrics and Molecular Microbiology at the US university and one of the study’s authors, explained that “Klebsiella pneumoniae is a serious threat to newborns who have not yet developed their own immune defenses.”
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