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Altered reactivity to measles virus in previously vaccinated children
Abstract:
In children vaccinated with killed measles vaccine, exposure to natural rubeola within two to four years can result in a clinical syndrome of altered measles reactivity.During a small epidemic of measles in Edmonton, Alberta, 51 children who had received their last killed measles vaccination 27 to 45 months before, were admitted to hospital with this syndrome.The syndrome consists of a prodromal cough and high fever followed by a maculopapular rash appearing on the extremities and progressing centrally. Pulmonary consolidations with or without pleural effusions were evident, but these cleared rapidly in four or five days. Initial WBC and ESR values suggested a bacterial etiology, but no pathogens could be isolated.Complement fixation titres for rubeola are present in acute and convalescent sera and indicate a definite measles infection.Previous killed measles vaccination excites a delayed hypersensitivity which is activated by the natural measles infection to account for this syndrome.It is recommended that killed measles vaccine be no longer used in routine vaccinations.
Insights
Children vaccinated with killed measles vaccine may develop a measles reactivity syndrome upon natural rubeola exposure. This syndrome, characterized by rash and pulmonary issues, indicates a delayed hypersensitivity reaction. Killed measles vaccine use is not recommended.
Area of Science:
- Pediatrics
- Immunology
- Infectious Diseases
Background:
- Killed measles vaccine was previously used in routine vaccinations.
- Exposure to natural rubeola (measles) can trigger altered immune responses in vaccinated children.
- A specific clinical syndrome has been observed in children previously vaccinated with killed measles vaccine.
Purpose of the Study:
- To describe the clinical syndrome of altered measles reactivity in children vaccinated with killed measles vaccine.
- To investigate the immunological basis of this syndrome.
- To provide recommendations regarding the use of killed measles vaccine.
Main Methods:
- Observational study during a measles epidemic in Edmonton, Alberta.
- Inclusion of 51 children vaccinated with killed measles vaccine 27-45 months prior.
- Clinical assessment, chest radiography, and serological testing (complement fixation titres for rubeola).
Main Results:
- Children presented with cough, high fever, and a progressing maculopapular rash.
- Pulmonary consolidations and pleural effusions were observed but resolved rapidly.
- Serological tests confirmed measles infection, with initial lab values suggesting bacterial etiology but no pathogens isolated.
Conclusions:
- Previous killed measles vaccination can induce a delayed hypersensitivity response.
- Natural measles infection can activate this hypersensitivity, leading to the observed clinical syndrome.
- It is recommended to discontinue the use of killed measles vaccine in routine immunizations.