A review of evidence for the use of pneumococcal conjugate vaccine in South Africa showed that children who are HIV positive are at significantly increased risk of pneumococcal disease, and so will benefit the most from vaccination, despite decreased vaccine efficacy in this group compared to healthy children.
Health
Vaccination can decrease childhood deaths from other causes (non-specific effects) above and beyond the expected direct impact of the vaccine
In a 2014 review of the non-specific effects of measles vaccines, among others, the WHO Strategic Advisory Group of Experts indicated that some studies of measles vaccine were suggestive (but not conclusive) of a beneficial effect of measles vaccine on overall mortality beyond the expected direct effect of the vaccine against measles. In particular, randomized control trials of children in Guinea- Bissau which looked at mortality up to the age of 9 months showed a low number of deaths post administration of the 3 doses of the measles vaccine over the study follow up period. Another trial in Nigeria also showed similar results.
In some cases, girls may reap greater health benefits from some vaccinations than boys
Across multiple studies reviewed, the effect of measles vaccine appears to be more beneficial to girls combating all-cause mortality when differences between vaccine effect in boys and girls was assessed.
Herd effects from immunization can protect children undergoing cancer treatments from infections
Children with cancer often rely on herd immunity as protection from vaccine-preventable diseases, so vaccinating family members and health workers is critical. Herd effects may be the only source of protection against diseases for which the vaccines are not recommended for immunosuppressed children, such as measles.
Cancer treatments can increase the risk of vaccine-preventable infections for children
Among children and young adults being treated for certain cancers, immunosuppressive therapies can erase immunity previously acquired through vaccination, dramatically increasing the risk of vaccine-preventable infections. The authors assert that vaccination during and after immunosuppressive treatment is necessary to rebuild immunity and protect the most at-risk children.
Children living in slums suffer from higher rates of diarrheal and respiratory illness
Children in slums suffer from higher rates of diarrheal and respiratory illness, malnutrition, and have lower vaccination rates. Mothers residing in slums are more poorly educated and less likely to receive antenatal care and skilled birth assistance.
Respiratory infections during pregnancy may exert indirect effects on the developing fetus
Respiratory infections during pregnancy may exert indirect effects on the developing fetus through placental function and maternal immune responses. This in turn may lead to pre-term births and reduced growth of the fetus. However, a review of recent studies, researchers show that administration of influenza vaccine during pregnancy adds 200 grams to newborn weight and that PCV7 vaccine given to infants translates into an additional 500 grams of growth in the first 6 months of life. In addition, maternal influenza vaccine led to a 15% reduction in low birth-weight. This indicates that immunization can improve intrauterine growth.
Immunization against tetanus, pertussis, and influenza can profoundly improve the health of pregnant mothers and their children
Immunization against tetanus, pertussis and influenza during pregnancy has been shown to have a profound effect on the health of the mother and fetus, and increases survival of infants in their first months of life. Maternal immunizations with tetanus toxoid-containing vaccines has been one of the main contributors to the 94% reduction in global deaths due to tetanus since 1988. Between the 1970s to the early 2000s, maternal immunization against pertussis brought disease incidence down to 5,000 cases per year from the earlier 100,000-250,000 cases per year in the United States. Vaccination of mothers for influenza has brought down confirmed cases of the disease by 63%.
Increases in immunization can save lives, particularly in low- and middle-income countries
Increased uptake of immunization for vaccine-preventable diseases, particularly in low- and middle-income countries, could save the lives of thousands of mothers and children each year. The disease burden of tetanus, influenza, and pertussis has been minimized in many countries through maternal immunization, but wider applications of this strategy are now needed.
Immunocompromised people are particularly vulnerable to IPD
In a long-term study of Canadian surveillance data researchers found that immunocompromised people were at a 12-fold risk of invasive pneumococcal disease (IPD) compared to healthy people. In addition, the risk of death from IPD in immunocompromised people was found to be 30-80% higher than healthy individuals who had contracted IPD. 10 years after introduction of PCV7 in Canada, the incidence of IPD due to serotypes included in the vaccine had decreased by 90%.