Severe local reactions to live measles virus vaccine following an immunization program

Area of Science:

• Immunology
• Vaccinology
• Public Health

Background:

• A measles immunization program in a Pennsylvania school district in February 1981 was followed by a cluster of nine severe local reactions.
• Investigating the cause of these adverse events is crucial for vaccine safety and public health strategies.

Purpose of the Study:

• To identify the underlying cause of severe local reactions following a mass measles immunization program.
• To determine if prior measles vaccination history was associated with the observed reactions.

Main Methods:

• A case-control study was conducted.
• Cases were defined as individuals experiencing severe local reactions.
• Controls were individuals from the same immunization program who did not experience such reactions.

Main Results:

• A statistically significant increase in the history of receiving killed measles vaccine was observed in cases compared to controls (p < .001).
• Cases also exhibited a statistically significant higher geometric mean measles antibody titer than controls (p < .01).

Conclusions:

• Previous receipt of killed measles vaccine was identified as the likely underlying cause of the severe local reactions.
• These findings highlight potential risks associated with specific measles vaccine formulations and inform future immunization practices.