Researchers at Simon Fraser University were among the earliest to discover the individualistic response that people have toward a vaccine or intervention, despite these being designed to treat the same condition.
The immunoglobulin heavy (IGH)-chain locus is responsible for producing genes that encode for different antibodies that are eventually used by B cells to fight off infections. These researchers sequenced the DNA in the IGH-chain locus in the chromosomes of 425 people of Asian, African and European descent. They located 11 possible large DNA insertions and deletions in the locus that were hypothesized to determine individualistic antibody gene count/diversity and, in some cases, disease susceptibility. This piece of comprehensive research was later integrated into the official human genome project assembly.
In another study, Rubella vaccines provoked significantly higher titers of neutralizing antibodies in children of African ethnicity compared to those of European descent or Hispanic ethnicity.
A U.S. study found significantly higher seroprevalence rates of antibodies to the measles virus in African Americans compared to Caucasians. Antibody titers to the pertussis vaccine were significantly and consistently higher in African American children compared to Caucasian children. In another study conducted in Northern Canada, native Innuit and Innu infants developed higher antibody titers to a measles vaccine compared with those of Caucasian descent.
Geographical and ecological factors also affect immune responses. Efficacy provided by the Bacillus Calmette-Guérin (BCG) tuberculosis vaccine has been shown to increase with a greater distance from the equator. The rotavirus vaccine, RotaTeq, also showed distinct patterns of efficacy in different geographical locations. Its effectiveness in preventing hospitalization and emergency room visits was 97% in the U.S., 95% in Europe and 90% in Latin America/Caribbic, but only 48.3% in Asia and 39.3% in Sub-Saharan Africa.
According to Dr. Chris Thompson, MD, an immunologist and associate professor of biology at Loyola University Maryland, factors that can influence a person’s reaction to a vaccine include health, genetics, nutrition, age, gender, preexisting immunity, environment and the use of anti-inflammatory medicines.