Measles Surge in Kerala

• 20 May 2019

Background

The state of Kerala has been witnessing the serious surge in the incidence of Measles since January 2019. This is in conformity with current global resurgence in measles.

Key Points

• Kerala reports around 600+ cases of measles every year. This year, as many cases have been reported in the first four months itself.
• Historically, measles has been a childhood disease. The epidemiological shift to older population presents new public health challenges because of the increased severity of the disease, especially in vulnerable populations like pregnant women and immunocompromised patients (HIV, organ transplant recipients on immunosuppressants, cancer patients), who cannot be vaccinated with the live attenuated measles vaccine.
• When universal routine immunization in childhood improves and the virus is still in circulation, the disease will naturally move to the older age group who may be unimmunized or whose vaccine-derived immunity has begun to wane.
• The first vaccination age for measles has been fixed at nine months because till then, the maternal antibodies transferred in utero are supposed to afford protection to the child.
• As a part of the national measles elimination strategy, a mandatory second dose at 15-18 months was introduced in 2010, so that there is better immune protection.
• It is fairly certain that those currently in the 18-40 years age group have not had the protection of the second dose and may be one reason for the increase in cases in this age group.
• However, some cases of death of infants younger than nine months due to measles, are also reported as young mothers may not have sufficient antibody protection.
• The changing epidemiology of measles has not just brought forth the several unknowns but also raised important questions on whether adult immunization should be a policy, on vaccine potency, the adequacy of vaccine immune response and consideration of third dose of MMR (mumps-measles-rubella).