Important note: This article is intended for those who understand vaccines as critical to maintaining their health and that of their families. It is NOT intended for those who are anti-vaccine and as such is NOT intended to foster a discussion on the merits of vaccines in this forum.
Because the current worldwide rise in allergic diseases (food allergies, eczema, asthma, et al) is happening at the same moment in time as infant vaccination rates are climbing, some have theorized that childhood vaccination may be responsible for the rise in allergic diseases.
A study recently published in the journal Allergy reviewed available literature published between 1946 and 2018 looking for some link between the two.
Searching the electronic databases PubMed and EMBASE (January 1946-January 2018), the authors selected papers containing vaccination and allergy terms.
Using random-effects meta-analysis, they estimated the pooled effects across studies. Because there was an inadequate number of homogeneous publications on newer and underused vaccines, the meta-analysis was limited to allergic outcomes following administration of (Bacillus Calmette-Guérin) BCG, measles and pertussis vaccination.
A total of 35 publications based on cohort studies and 7 publications based on randomized controlled trials (RCTs) met the inclusion criteria. RCTs: From 2 studies, early vaccination with BCG vaccine was associated with a reduced risk of eczema (RR = 0.83; 95% CI = 0.73-0.93; I2 = 0%) but not food allergy or asthma. No association was found between the pertussis vaccine and any allergic outcome based on a single RCT.
Childhood measles vaccination was associated with a reduced risk of eczema (RR = 0.65; 95% CI = 0.47-0.90, I2 = 0.0%), asthma (RR = 0.78; 95% CI = 0.62-0.98, I2 = 93.9%) and, with a similar, statistically non-significant reduction in sensitization (RR = 0.78; 95% CI = 0.61-1.01, I2 = 19.4%).
The study found no evidence that childhood vaccination with commonly administered vaccines was associated with increased risk of later allergic disease. The results from their pooled analysis of both RCTs and cohort studies suggest that vaccination with BCG and measles vaccines were associated with a reduced risk of eczema.