VoICE Immunization Evidence: Cognition
Evidence suggests that vaccinated children may have better cognitive function than unvaccinated children.
Key Evidence: A 2019 analysis of survey data from India, Ethiopia and Vietnam found that children vaccinated against measles scored better on cognitive tests of language development, math and reading than children who did not receive measles vaccines.
Key Evidence: A small study from the Philippines, published in a Working Paper from Harvard University, found that children immunized with 6 basic vaccines scored better on three cognitive tests (verbal, mathematics and language) at age 11 compared to children who received none of these 6 vaccines.
Key Evidence: A large longitudinal study in the Philippines found that children suffering bouts of diarrhea and respiratory infections were at a significantly increased risk of physical stunting which is associated with “poor functional outcomes such as impaired cognitive development.”
Key Evidence: A study looking at the long term cognitive deficits faced by children in an urban Brazilian shantytown with high incidence of diarrhea in the first two years of life showed that this cohort scored significantly lower on 3/5 types of test measuring cognitive function at ages 6-10 compared to children who did not suffer recurrent bouts of early childhood diarrhea. In particular, the children who suffered from persistent early childhood diarrhea scored lower on tests assessing nonverbal intelligence (TONI) and IQ through assessing ability to match symbols to numbers (WISC-III Coding task) and short-term memory (WISC-III digit scan).
Key Evidence: A study analyzing the long-term consequences of middle ear disease in children in an urban health center and a private practice in the United States found that time spent with middle ear effusion during the first 3 years of life was significantly associated with lower school performance and lower scores in cognitive ability, speech, and language.
Survivors of serious vaccine-preventable diseases frequently suffer from cognitive impairment and neurological sequelae.
Key Evidence: The risk of mortality from tetanus is high for mothers and their newborns, and up to 50% of children who do survive neonatal tetanus may have long-term cognitive impairment, according to a 2007 review.
Key Evidence: In The Gambia, 58% of children who survived pneumococcal meningitis had long lasting negative health outcomes. Half had major disabilities such as mental retardation, hearing loss, motor abnormalities, and seizures.
Key Evidence: In a systematic literature review of studies in Africa, it was found that 25% of children who survived pneumococcal or Hib meningitis had neuropsychological deficits.