Why Premature Babies Are Missing Critical First Vaccines—And What Parents Should Know

Only two-thirds of premature babies in southwestern Uganda are receiving their first critical vaccines, leaving thousands of vulnerable infants unprotected against serious diseases like tuberculosis and polio, according to new research from Mbarara University of Science and Technology.

The study, which followed 350 preterm infants over several months, found that just 66.6% received both Bacillus Calmette-Guerin (BCG) and birth dose Oral Polio Vaccine (OPV0)—well below Uganda's national target of 90% coverage. Even more concerning, only 28% of these premature babies received the polio vaccine, compared to 65.4% who got the tuberculosis vaccine.

Why Are Premature Babies More Vulnerable to Disease?

Premature infants face unique challenges that make timely vaccination even more critical than for full-term babies. Their immune systems are significantly compromised because they miss out on important antibodies normally transferred from mother to baby during the third trimester of pregnancy. Additionally, their B-cells—the immune cells that produce antibodies—are still immature, making it harder for them to fight off infections.

"These deficits not only result in lower baseline protective antibodies but also mean that passively acquired maternal antibodies wane to undetectable levels as early as 4 months of life," the researchers explained, noting this creates a "diminished ability to mount robust, self-generated defenses against diseases."

What Factors Influence Whether Preterm Babies Get Vaccinated?

The research identified several key factors that determine whether premature infants receive their essential first vaccines. The study found that certain circumstances significantly improved vaccination rates, while others created barriers:

• Infant Age: Older preterm infants were more likely to be vaccinated, suggesting delays in initial vaccination scheduling
• Maternal Care: Regular antenatal care attendance by mothers increased the likelihood their premature babies would receive vaccines
• Hospital Recommendations: When hospitals specifically recommended vaccination before discharge, vaccination rates improved significantly
• Initial Denial: Surprisingly, being denied vaccination at the first hospital visit negatively influenced future vaccination attempts

The median age of the preterm infants in the study was 13 weeks, with a median birth weight of 1.6 kg (approximately 3.5 pounds). This suggests many of these vulnerable babies were going months without protection against preventable diseases.

Why Does This Vaccination Gap Matter?

The consequences of delayed vaccination extend far beyond individual babies. When vaccination rates fall below targets, entire communities become vulnerable to disease outbreaks. Uganda experienced this firsthand in 2021 with a polio outbreak that health officials attributed to delayed infant vaccination. More recently, measles outbreaks have been reported across several districts, including the western region where this study took place.

For premature babies specifically, the stakes are even higher. These infants are already at increased risk for complications, and vaccine-preventable diseases can be particularly severe. The delay in receiving BCG vaccine is especially concerning given that preterm infants are more vulnerable to tuberculosis exposure, particularly in regions with high tuberculosis prevalence like Uganda.

The research highlights an urgent need for healthcare systems to develop better protocols for ensuring premature infants receive their vaccines before hospital discharge. With Uganda's neonatal mortality rate at 22 deaths per 1,000 live births, and prematurity being the leading cause of neonatal death often complicated by infections, timely vaccination could play a crucial role in saving lives.