Investigation of MMR Vaccination Rates and its Relationship with Measles, Mumps, and Rubella Outbreaks in California

Abstract

<b>Abstract ID 23246</b> <b>Poster Board 431</b> <b>Background:</b> There have been growing concerns of measles outbreaks in the United States. In 2019, more than 1200 cases of measles were reported in the US, the highest annual number since 1992. Eighty-nine percent of measles patients were unvaccinated or had an unknown vaccination status. The potential resurgence of measles could be due to the declining vaccine coverage as a result of vaccine hesitancy and an ever-growing number of anti-vaccination movements. Vaccine hesitancy negatively affects vaccine coverage and therefore the herd immunity conferred unto non-immune individuals. A recent data suggests that a 5% drop in MMR vaccination coverage leads to a threefold increase in measles cases per year. This is equivalent to $2.1 million in cost to the public sector thus constituting a significant economic burden to the US healthcare system. The measles, mumps, and rubella (MMR) vaccine is an important vaccination among children. Any drop in the MMR vaccination rates most likely to increase the risk of measles, mumps and rubella outbreaks in population. <b>Objectives:</b> The aim of this study was to examine the MMR vaccination rates among Kindergarteners and its relationship with measles, mumps and rubella outbreaks in population of California. <b>Methods:</b> Publicly available data on MMR vaccination rates among Kindergartens in California between 2015 and 2019 were obtained from the Center for Disease Control and prevention (CDC). Whereas publicly available data on measles, mumps and rubella cases were obtained from California Department of Public Health and other published reports. Changes in incidence rates were assessed by time-trend analysis. The rates of MMR vaccination rates were compared between 2015 to 2019. MMR vaccination rates were also compared with measles, mumps, rubella outbreaks using correlational analysis. A p-value of &lt;0.05 was considered statistically significant. <b>Results:</b> Over a five-year period, vaccination rates among Kindergarteners ranged between 92.6% to 96.5%. The median MMR vaccination rate was 96.5%. A total of 259 cases of measles, 810 of mumps and seven cases of rubella were observed over five-year period. The median number of cases was 24 and 140 for measles and mumps, respectively, and zero for rubella. The MMR vaccination rates were dropped from 2015 to 2019 (96.5% vs. 92.6%, p&lt;0.05). Similarly, the rates (cases/100,000) of outbreaks were increased for measles (0.18 vs. 0.32, p&lt;0.05), mumps (0.08 vs. 0.89, p&lt;0.05) and rubella (0.0 vs. 0.01, p&lt;0.05) from 2015 to 2019. MMR vaccination rates correlated with measles, mumps and rubella (r= -0.90, 0.70, 0.67) outbreaks respectively but were not statistically significant except for measles. No significant trends were observed for disease outbreaks. <b>Conclusions:</b> Decline in MMR vaccination rates and increase in mumps, measles and rubella outbreaks is a major public health concern. Increase in MMR vaccination, improved disease surveillance and rapid outbreak containment are essential in curbing the measles, mumps, rubella outbreaks in California and in the US and it deserves serious attention of policy makers, public health experts and society at large.