Immunization

By preventing infection, immunization should theoretically reduce the impact of illness on child nutrient and calorie intake. In Peru, policymakers prioritized introduction and scale up of pneumococcal conjugate vaccine (PCV) and rotavirus vaccine.

Literature Review

There is currently limited global evidence showing any direct relationship between vaccines and linear growth.

Quantitative Analysis

Based on the linear mixed effects regression, PCV significantly (at the 1 percent level) influenced stunting prevalence in the expected direction for 2000-2016 period. The effect size of 0.03 was small. However, PCV coverage rate was not significant for the 2008-2016 period.

Rotavirus vaccine coverage was not significantly associated with stunting prevalence.

Neither PCV nor rotavirus vaccine coverage was significant in the multivariate regression used to inform the Oaxaca-Blinder decomposition analysis. This is likely because both vaccines were introduced and scaled up after 2008, giving them fewer data points for inclusion in the analysis.

Qualitative Analysis

Childhood disease prevention was noted as a main driver of stunting reduction by interviewees; within this, vaccination was mentioned explicitly. Low spending on vaccines was cited as a reason for high stunting rates prior to 2007.

“The substantial increase occurred in 2008. We introduced rotavirus and pneumococcal vaccines, but we had also implemented other vaccines: hepatitis B, influenza, H. influenzae. The vaccine budget increased from 70 million to 400 million soles.”

- Technical Officer, Ministry of Economy and Finances.

Conclusion

Immunization, specifically with PCV and rotavirus vaccine, has a plausible biological pathway to stunting reduction, mediated by reduced incidence of childhood and maternal illnesses. However, the direct relationship between immunization and stunting prevalence has not been ascertained.

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