Hand, Foot and Mouth Disease (HFMD): Prevalence and its Spatial Relationship with Vaccine Refusal Cases in Terengganu, Malaysia

Abstract

Hand, foot and mouth disease (HFMD) is a global public health problem with pandemic potential. The progressive increment of HFMD cases in Malaysia needs further investigation to identify the pattern of disease spread, including its proximity to vaccine refusal. We sought to estimate the prevalence of HFMD in Terengganu and determine the spatial relationship between HFMD and vaccine refusal cases. This study employed data from the national electronic communicable disease notification system and vaccine refusal database maintained by the Communicable Disease Control (CDC) Unit and Maternal and Child Health Care (MCH) Unit. Data from all cases recorded in 2016 were provided by the Terengganu State Health Department, Malaysia. The number of HFMD cases for each district was estimated using the points-in-polygons function in R software. The spatial relationship between HFMD cases and vaccine refusal cases was tested using the cross K-function test. A total of 811 HFMD cases was notified in 2016, with the overall prevalence at 80.2 cases per 100,000 population. Among all districts in Terengganu, the prevalence of HFMD ranged from 19.2 to 230.9 cases per 100,000 population, with the cases highly concentrated in three districts: Kuala Terengganu, Marang, and Dungun. There was evidence of a spatial cluster of HFMD cases based on the Nearest Neighbour Index, r = 0.27 (p-value < 0.01). Moreover, the locations of HFMD cases were statistically and closely related to the areas of vaccine refusal cases (cross K test, p-value < 0.010). The prevalence of HFMD from year to year was high. HFMD cases and vaccine refusal cases formed clusters in the districts with a high-density population. The proximity of HFMD cases and vaccine refusal cases in Terengganu warrants further investigation.