Our study shows that people who search for meningitis on Google looked for definitions of the disease and its symptoms. The majority of searches came from the developing countries. This was consistent with the literature that affirms that the morbidity and mortality burden of meningitis are much greater in resource-poor nations . As for the vaccine keywords, the majority searched for general information on the vaccine, the nearest place to get them and their frequency of administration. Interestingly, most of the searches came from the developed countries. This may be due to the lower disease burden of meningitis as shown by their case numbers. Moreover, these nations are already working on prevention rather than acute infection. The pattern of keyword searching that certain countries employ may possibly give public health workers an indication on the current phase of a region in the epidemic stage spectrum. In our study, the countries battling ongoing epidemics are searching for definitions, signs and symptoms, while developed countries are inclined to focus on prevention and are searching for vaccine information, timing and location.
The number of cases of meningitis worldwide showed a generally decreasing trend; however, online search interest was slowly increasing. This can be due to multiple factors such as increasing awareness of the disease, expanding internet access and the rising importance of prevention. An exception to this observation was a sudden drop in search interest in May 2020 and this may be due to the coronavirus disease (COVID-19) pandemic dominating search interest globally. The increase in search volumes for the influenza, BCG, and pneumococcal vaccines beginning March 2020 were likewise likely related to vaccine interest amidst the COVID-19 pandemic. These underscores again the role of the internet in health-seeking behavior and health education: even if global prevalence decreases, the internet may be used to facilitate and sustain awareness, prevention, and treatment of meningitis. The internet becomes part of the armamentarium of public health both in prevention and management in developed and developing countries.
Google Trends not only provides baseline search data over time, but they also provide insight into sudden spikes in search volume. In the case of meningitis, there were four notable spikes in search volume throughout the past 12 years. On further investigation, these spikes coincided with news events at those times.
In October 2012, there was an outbreak of fungal meningitis associated with the New England Compounding Center (NECC) in the United States. It was found that the NECC has been compounding injections of steroids contaminated with Exserohilum rostratum and Aspergillus fumigatus .
February 2016 was an eventful month due to overlapping international events. First, there was a large outbreak of pneumococcal and meningococcal meningitis in Ghana, Africa . Second, there was likewise a spike of cases in Tuscany, Italy during a meningitis epidemic that has been ongoing since 2015 . At the same time in the United Kingdom, the daughter of Matt Dawson, a British professional football player, died of meningococcal meningitis . This spurred a petition making meningococcal vaccinations mandatory for children up to 11 years old. The petition gathered 823,349 signatures by its conclusion . Meanwhile in the United States, there was an outbreak among students in Santa Clara University, California and likewise contributed to the interest in vaccination . Unsurprisingly, the top three countries with the highest search interest in this period were Ghana, Italy, and the United Kingdom.
The peak in January 2017 was caused mainly by searches coming from Italy. While this interest was not due to increasing cases, there was a highly publicized shift in the policies of local health authorities that strengthened vaccine coverage and allowed substantial savings up to 50% with the assistance of insurance . This announcement was made on December 29, 2016 and media coverage lasted up to May 2017.
Finally, the most recent spike occurred in March 2019. This was when former Brazilian president Luiz Inacio Lula da Silva, who was imprisoned for corruption allegations, was given temporary leave to attend his grandson’s funeral who died of meningitis . Both the prison furlough and funeral garnered media attention.
These patterns show that traditional media such as television, radio and newsprint still have a role in disseminating health information. These media can serve as gateways to information and spur further health-seeking behavior at the user’s own time and convenience. In order to have a successful public health information policy, both traditional media and internet must be used together.
The present analysis showed that while there were statistically significant correlations between meningitis and the BCG and meningococcal vaccines; the relationships appeared weak. It was also unclear if these correlations correspond to the overall decrease in meningitis cases worldwide. There were no correlations seen with the other vaccines. There was clear seasonal interest in the influenza vaccine, but this was not observed in meningitis. Search interests in meningitis, therefore, do not appear to correlate with search interests in vaccine or its number of cases.
Counterintuitively, these results are not entirely unexpected. As previously discussed, the internet may play a role in the sustenance of awareness and search interest in meningitis despite its decreasing numbers worldwide. As for the weak to absent correlations of meningitis with vaccines, it may be possible that the messaging of these vaccines is not clear as they relate to meningitis. Another possibility is that the other complications of tuberculosis and meningococcus such as disseminated TB or meningococcemia are emphasized. This means that meningitis alone may not be a sufficient surrogate measure for vaccine awareness and that other related illnesses must be investigated as well. Meningitis is not the only complication these vaccines prevent. For health workers who will undergo similar studies in the future, search terms must be selected holistically and should reflect the full spectrum of the disease to detect more nuanced correlations.
There were several limitations to this study. First, this study was confined to Google searches and did not measure search interest in social media. While there were spikes in search interest in meningitis, these were attributable to meningitis dominating news headlines. The extent of how specific social media platforms could have contributed to search interest is unknown. The study was also subject to the penetration of internet access as not all countries may have the same ability or extent to perform Google searches. In effect, this study was only able to measure the search behavior of those with internet access and may underrepresent resource-poor countries. Another limitation was that the Global Burden of Disease Database reports all-cause meningitis and does not differentiate bacterial, viral, fungal, or tuberculous meningitis. Finally, there was paucity of validated data on Google search behavior and other online behavior such as in social media. It is then difficult to establish true causality and relationships between search terms. The possible explanations discussed in this analysis are hypotheses which warrant further study.
While Google Trends results are increasingly being used to provide general study of online search behavior, future infodemiological studies can focus on social media for a more precise and granular evaluation of internet behavior. Not only will these future studies use search data, but internet crawlers may be programmed to measure interactions and engagement, analyze semantics and even perform big data analytics for improvement of public health and policy.