Case-control study on correlation between medical care seeking and high incidence of measles

Objective To understand the reason for the increase of measles incidence in Shaoxing, Zhejiang province in 2013. Methods The correlation between medical care seeking and high incidence of measles was analyzed through a case-control study of 166 laboratory diagnosed measles cases and 498 age-matched controls living in same areas. The study was conducted from January to June 2013. All the subjects completed the questionnaires on risk factors for measles, household survey record forms and written informed consents. Data were analyzed by using Pearson 2 test, Mantel-Haenszel 2 test, T-test of independent sample and Cox proportional hazards regression model. Results Medical care seeking during measles incubation period was correlated with the reported increase of measles incidence, the OR was 9.08(95% CI:2.58-31.95)among children aged 7 months, 13.01 (95% CI: 2.85-59.40) among children aged 7 months to 14 years, and 16.53 (95%CI:8.16-33.47)among children aged 15 years. Cox proportional hazards regression analysis indicated that medical care seeking due to respiratory symptoms including cough and fever, was the risk factor to be attacked by measles (ORMH=36.21, 95% CI:4.56-289.16).Staying in treatment room (OR=3.72, 95% CI:1.06-13.04) and ward (OR=8.50,95% CI:1.70-42.38) had higher risk than staying in registration room and consulting room. Conclusion Strong correlation between hospital exposure and high incidence of measles do exist. Inappropriate triage of patients in hospitals and insufficient ventilation in treatment rooms and wards were the major risk factors.