In February and March 2020, there was a peak in worldwide interest in pneumococcal and influenza vaccines, which coincided with the COVID-19 pandemic, according to a study recently published in Vaccine.

“Our findings may foreshadow changes in vaccination rates in the near future,” Edward Christopher Dee, Harvard Medical School, and his colleagues wrote. “Though vaccine coverage is largely a function of the health care system, public perception of vaccines may lead to massive changes in immunization rates.”

This infodemiology study investigated the correlation between online interest in COVID-19 and interest in routine vaccinations recommended by the CDC. The data was based on Google’s search volume index (SVI), which estimates the volume of online search activity relative to the highest volume of searches within a specified period. SVIs from December 30, 2019 to March 30, 2020 were collected for ‘‘coronavirus (Virus)” and compared with SVIs of search terms related to adult vaccines such as flu, tetanus, measles, and shingles. 

To account for seasonal variation, SVIs from December 30, 2019 to March 30, 2020 were compared with SVIs from the same months in 2015-2019. A country-level analysis in ten COVID-19 hotspots and ten countries with low disease burden was also performed.

There were significant positive correlations between SVIs for ‘‘coronavirus (Virus)” and search terms for pneumococcal (R = 0.89, p < 0.0001) and influenza vaccines (R = 0.93, p < 0.0001) in 2020. This was greater than SVIs for the same terms in 2015-2019 (p = 0.005, p < 0.0001, respectively). SVIs for ‘‘coronavirus (Virus)” and search terms for influenza and pneumococcal vaccines showed a marked peak in March 2020.

SVIs for ‘‘coronavirus (Virus)” were negatively correlated with other vaccine search terms such as HPV, shingles, Hepatitis A, Hepatitis B, and meningococcal.

Eight in ten COVID-19 hotspots demonstrated significant positive correlations between SVIs for coronavirus and search terms for pneumococcal and influenza vaccines. When correlating local SVIs for the pneumococcal vaccine and coronavirus, the range of significant R values of the countries with the highest and lowest incidence were 0.37-0.91 and 0.29-0.39, respectively.

Dee and his colleagues believe this study presents “... an opportunity for further studies into approximating vaccine demand and improving health education that could mitigate future disease outbreaks and possibly impact other aspects of public health.”