Poor nutrition lowers protection against measles, tetanus, and Hib in fully vaccinated children, revealing the critical role of nutrition in immunity.

New research reveals that immunity relies on proper nutrition more than vaccination alone. Conducted as part of the VHEMBE birth cohort in rural South Africa, the study examined the relationship between undernutrition and immunity in fully vaccinated children. The findings showed that undernourished children—those with stunting or poor growth—had significantly lower antibody levels for measles, tetanus, and Haemophilus influenzae type b (Hib) compared to well-nourished peers, highlighting nutrition’s pivotal role in building immunity.

By age five, 90.4% of children were protected against measles, 66.7% against tetanus, and 56.1% against Hib. Undernourished children exhibited a 24% to 27% drop in measles antibodies, and stunted girls experienced a 37% reduction in tetanus antibodies. The study found that Hib immunity was the weakest overall, with only 56.1% of children protected. These findings emphasize that the immune system’s ability to protect against disease depends on proper nutrition, regardless of vaccination status.

Nutrition: The Real Foundation of Immunity

The immune system relies on key nutrients to function effectively. Vitamins A, D, zinc, and iron deficiency disrupt the production of immune cells, including B-cells and T-cells, which are necessary for creating antibodies. This study demonstrates that proper nutrition, rather than vaccination alone, is essential for building and maintaining effective immunity.

Vaccine-Specific Findings

The study analyzed antibody responses to three vaccines:

• Measles: A live-attenuated virus vaccine.
• Tetanus: An adjuvanted protein vaccine.
• Hib: An aluminum-salt adjuvanted, conjugated polysaccharide vaccine.

Overall, measles immunity appeared strong, but undernourished children had a 24% to 27% reduction in antibody levels, underscoring how nutrition, not vaccination alone, supports the immune system’s ability to respond effectively.

Tetanus immunity showed an even sharper decline, with stunted girls experiencing a 37% reduction in antibody levels, leaving them more vulnerable despite being vaccinated.

Hib immunity was the weakest, with only 56.1% of children protected. Reduced antibody levels in undernourished children further highlight that nutrition plays a larger role than vaccines in determining protection.

Implications for Public Health

Globally, 148 million children under the age of five are stunted, primarily in sub-Saharan Africa and Asia. Stunting hinders physical development and weakens immunity, reducing the ability to respond to infections. Malnutrition, rather than vaccine schedules, appears to be the primary determinant of immune effectiveness, leaving undernourished children more vulnerable to disease.

Addressing Nutritional Gaps

Focusing on nutrition is critical to building a strong immune system and fighting diseases. Effective strategies include:

• Nutritional Supplementation: Essential nutrients like vitamin A, zinc, and iron support immune cell production.
• Breastfeeding Support: Extended breastfeeding supplies vital nutrients and immune-boosting factors essential for early immune development.
• Healthy Diets: Introducing whole, nutrient-rich foods and avoiding junk food enhances immunity beyond the effects of vaccines alone.

Breaking the Cycle of Malnutrition

Undernutrition both weakens the immune system and perpetuates a cycle of illness. Children with weakened immunity are more prone to infections, further depleting already compromised systems. This study clarifies that breaking this cycle requires addressing nutrition as a foundational factor in disease prevention and immunity building.

Citation:

Eskenazi B, Rauch S, Elsiwi B, et al. Undernutrition and antibody response to measles, tetanus, and Haemophilus Influenzae type b (Hib) vaccination in pre-school South African children: The VHEMBE birth cohort study. Vaccine.2024. https://doi.org/10.1016/j.vaccine.2024.126564.