Spatio-temporal dynamics of measles outbreaks in Cameroon

PURPOSE

In 2012, Cameroon experienced a large measles outbreak of over 14,000 cases. To determine the spatio-temporal dynamics of measles transmission in Cameroon, we analyzed weekly case data collected by the Ministry of Health.

METHODS

We compared several multivariate time-series models of population movement to characterize the spatial spread of measles in Cameroon. Using the best model, we evaluated the contribution of population mobility to disease transmission at increasing geographic resolutions: region, department, and health district.

RESULTS

Our spatio-temporal analysis showed that the power law model, which accounts for long-distance population movement, best represents the spatial spread of measles in Cameroon. Population movement between health districts within departments contributed to 7.6% (range: 0.4%-13.4%) of cases at the district level, whereas movement between departments within regions contributed to 16.0% (range: 1.3%-23.2%) of cases. Long-distance movement between regions contributed to 16.7% (range: 0.1%-59.0%) of cases at the region level, 20.1% (range: 7.1%-30.0%) at the department level, and 29.7% (range: 15.3%-47.6%) at the health district level.

CONCLUSIONS

Population long-distance mobility is an important driver of measles dynamics in Cameroon. These findings demonstrate the need to improve our understanding of the roles of population mobility and local heterogeneity of vaccination coverage in the spread and control of measles in Cameroon.

Media content about vaccines in the United States and Canada, 2012-2014: An analysis using data from the Vaccine Sentimeter

BACKGROUND

A system for monitoring vaccine-related media content was previously developed and studied from an international perspective. This monitoring approach could also have value at a regional level, but it has yet to be evaluated at this scale. We examined regional patterns of vaccine-related media topics and sentiment in the US and Canada.

METHODS

We extracted vaccine-relevant US and Canadian online media reports between June 2012 and October 2014 from the Vaccine Sentimeter, a HealthMap-based automated media monitoring system for news aggregators and blogs. We analyzed regional distributions of reports about vaccines, categories (i.e., topics), sentiment, and measles outbreaks.

FINDINGS

The Vaccine Sentimeter captured 10,715 reports during the study period. Negative sentiment was highest in reports about vaccine safety (47%), Hepatitis B (19%), and Vermont (18%). Analyses of measles outbreaks revealed geographical variation in media content. For example, religious beliefs were mentioned in 27% of measles reports in Texas and 22% of British Columbia reports, but there were no references to religion in media on measles from California.

INTERPRETATIONS

A regional analysis of online sentiment towards vaccine can provide insights that may give US and Canadian public health practitioners a deeper understanding of media influences on vaccine choices in their regions and consequently lead to more effective public health action.

Vaccine hesitancy in Austria : A cross-sectional survey

BACKGROUND

Vaccine hesitancy is an emerging phenomenon particularly in industrialized nations. It has led to repeated epidemic outbreaks of otherwise vaccine-preventable, infectious diseases. Compared to other countries very low rates of influenza and measles vaccination rates have been reported in Austria.

METHODS

We performed a single-center cross-sectional, questionnaire-based survey. A total of 350 adult patients attending our emergency room participated in this survey. We assessed knowledge and attitudes towards vaccination and the associated infectious diseases.

RESULTS

Out of 350 participants 40 (11.4 %) declared that they deliberately refused vaccinations. Most common reasons for non-vaccination were fear of adverse effects (35.9 %), doubt of effectiveness of vaccines (35.9 %) and distrust towards the pharmaceutical industry (23.1 %). Of all 350 participants only 148 (42.3 %) thought themselves to be sufficiently informed about national vaccination recommendations as stated in the Austrian National Vaccination Program (ANVP). General practitioners (GP) were the primary source of healthcare-related information for 256 (73.1 %) participants. Furthermore, GPs as well as hospital-based physicians achieved the highest level of trust in this study population.

CONCLUSIONS

The results of our study underline the necessity of comprehensive informational campaigns on the merits of vaccination. A lack of knowledge about the benefits of vaccination, uncertainty and unfounded fears seem to prevent the achievement of recommended vaccination rates. Family GPs enjoyed the highest levels of trust in our study population. We believe that additional information communicated by GPs could help boost the low vaccination rates. This study underlines the important role of primary care practitioners in informing patients about vaccines and healthcare topics.

Implication of health care personnel in measles transmission

Healthcare personnel (HCP) play an important role in transmission of highly contagious diseases such as measles. Current immunization guidelines in Catalonia include Measles-Mumps-Rubella (MMR) immunization for HCP born after 1967 without evidence of immunity. Despite high vaccination coverage (90%) a high burden of measles cases related to outbreaks have occurred. The aim of this study was to assess the implication of HCP in measles transmission related to healthcare setting. A review of surveillance case data from 2001 to 2013 gathered through the Measles Elimination Program in Catalonia was performed. Twenty six outbreaks involving 797 cases were reported, 52 (6.5%) were HCP aged 21-41 years, 72,5% (38) patient were care personnel (doctors and nurses) and 22,5% (14) other health care related personnel. Forty six 87%) were unvaccinated, 4(10%) had only one dose and 2 had two doses of MMR. In community outbreaks 30 clusters with HCP involved were observed, yet none were identified as index cases. Non-vaccinated HCPs against measles were all under 45 years of age. Vaccination is the only reliable protection against nosocomial spread of measles from HCPs. Assessing vaccination status of HCPs and implementing a 2 dose vaccination in those lacking evidence of immunity is needed in order to set to zero the risk of acquiring and spreading measles in healthcare (HC) settings.

Lack of herd immunity against measles in individuals aged <35 years could explain re-emergence of measles in Catalonia (Spain)

OBJECTIVES

The objective of this study was to assess the association between lack of herd immunity in some population groups and the re-emergence of measles in Catalonia in 2006.

METHODS

Herd immunity was considered established in the different population groups when the prevalence of positive serological results to measles was higher than the herd immunity threshold of 90%. The Chi-square test and the odds ratio were used to assess the association between lack of herd immunity and measles cases in the outbreak of 2006-2007.

RESULTS

Herd immunity was not established against measles in individuals aged 0-14 years and 25-34 years, as the prevalence of positive serological results was <90% in these groups. In the measles outbreak of 2006-2007, 91% of cases occurred in age groups without herd immunity, and only 9% of cases occurred in age groups with herd immunity (p<0.001). The odds ratio for the association between lack of herd immunity and measles cases in the outbreak of 2006-2007 was 104 (p<0.001).

CONCLUSION

Lack of herd immunity in individuals aged<35 years could be one of the factors underlying the re-emergence of measles in Catalonia.