This 2013 review summarizes data from several randomized trials in which measles and tuberculosis vaccines were associated with a substantial reduction in overall child mortality, which cannot be solely explained by prevention of the target disease. These studies suggest that in addition to disease-specific effects, some live vaccines may also provide “nonspecific effects” that enhance the immune system’s ability to protect against additional pathogens.
Tuberculosis/BCG
Administration of vaccines can also decrease childhood deaths from other causes, above and beyond the expected direct impact of the vaccine
Three randomized controlled trials enrolling a total of over 6500 infants over 12 consecutive years in Guinea-Bissau found a 38% reduction in all-cause neonatal mortality associated with early vaccination with BCG. Revisiting these trials to explore the seasonal variation in this effect, it was found that early vaccination with BCG was particularly beneficial when administered between November and January, coincident with peaking malaria infections.
Investments in polio eradication in Africa improved overall immunization systems and increased coverage of routine vaccinations
A systematic review of 8 African countries that had wild polio virus transmission and significant polio eradication activities found evidence that the huge investments made in polio have strengthened capacity in almost all aspects of the overall immunization systems, especially in the areas of microplanning, service delivery, capacity-building (especially supportive supervision and on-the-job training), and program management. This led to substantial increases in coverage of other routine vaccinations – BCG, DPT, measles – in all 8 countries over a 25-year period (1989-2014), including a more than a 3-fold increase in DPT3 coverage in 2 countries and a more than a 2-fold increase in 3 other countries.
Tetanus vaccination during pregnancy in India reduces delayed vaccination in children, especially for those born at home
In India, children whose mothers received tetanus vaccination during their pregnancy were 22-31% less likely to have delayed vaccination (depending on the vaccine) than children of unvaccinated mothers. Those born at home were nearly 3 times more likely to receive BCG vaccination late and 41% more likely to receive their first dose of DTP late than those born in a public health facility.
Children from the poorest households in India are more likely to have delayed vaccinations, increasing disease risk
Indian children in households from the lowest wealth quintile were 30-95% more likely to be delayed in their vaccinations than those from the wealthiest households [depending on the vaccine]. Delayed vaccination increases the window of susceptibility to vaccine preventable diseases and can lead to outbreaks.
Data in this analysis was from the National Family and Health Survey 4.
Children of mothers with no education or primary education are more likely to have delayed vaccinations
A study of delayed vaccination in India found that children whose mothers had no formal education were 37-81% more likely to have delayed vaccinations than children of mothers with 12 or more years of schooling [depending on the vaccine]. Children whose mothers had a primary school eduction fared only slightly better with 33-62% greater odds of getting their vaccination late, when compared to those with highly educated mothers.
Data in this analysis was from the National Family and Health Survey 4.
Screening tests in Italy found high rates of infectious diseases in newly-arrived migrants, emphasizing the need for universal screening
Screening tests given to more than 300 newly-arrived economic migrants and asylum seekers in Italy — the majority from sub-Saharan Africa — found high rates of chronic hepatitis B infection and latent and active tuberculosis (with 8% having signs of current infection or active TB). These findings underscore the important of universal screening for infectious diseases for all newly-arrived migrants.
Immunization is important for recent migrants to overcome health barriers and prevent diseases like tuberculosis
Recent migrants face barriers to accessing health care including language and cultural barriers, limited knowledge, food and housing insecurity, stress, and lack of resources available during prolonged travel. In Canada, though foreign-born populations make up only 22% of the total population, 70% of active tuberculosis cases occurred in this population.
Immunization can help overcome barriers to healthcare access and reduce high rates of TB in Inuit populations
Native populations experience barriers to health care access such as limited knowledge, stigma, community social isolation, and geographic isolation. As a result, Inuit populations in Canada suffer 300 times higher rates of TB than the Canadian-born non-Indigenous population.
Children of younger Bangladeshi mothers had a higher chance of incomplete vaccination compared to older mothers
Children of Bangladeshi mothers younger than 34 years were more than three times as likely to have incomplete vaccination compared to children of mothers older than 35 years.