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The human papillomavirus (HPV) vaccine is recommended for adolescents and young adults to prevent HPV-related cancers and genital warts. However, HPV vaccine uptake among the target age groups is suboptimal.
The aim of this infodemiology study was to examine public online searches in the United States related to the HPV vaccine from January 2010 to December 2021.
Google Trends (GT) was used to explore online searches related to the HPV vaccine from January 1, 2010, to December 31, 2021. Online searches and queries on the HPV vaccine were investigated using relative search volumes (RSVs). Analysis of variance was performed to investigate quarterly differences in HPV vaccine searches in each year from 2010 to 2021. A joinpoint regression was used to identify statistically significant changes over time; the α level was set to .05.
The year-wise online search volume related to the HPV vaccine increased from 2010 to 2021, often following federal changes related to vaccine administration. Joinpoint regression analysis showed that HPV vaccine searches significantly increased on average by 8.6% (95% CI 5.9%-11.4%) across each year from 2010 to 2021. Moreover, HPV vaccine searches demonstrated a similar pattern across years, with search interest increasing through August nearly every year. At the state level, the highest 12-year mean RSV was observed in California (59.9, SD 14.3) and the lowest was observed in Wyoming (17.4, SD 8.5) during the period of 2010-2021.
Online searches related to the HPV vaccine increased by an average of 8.6% across each year from 2010 to 2021, with noticeable spikes corresponding to key changes in vaccine recommendations. We identified patterns across years and differences at the state level in the online search interest related to the HPV vaccine. Public health organizations can use GT as a tool to characterize the public interest in and promote the HPV vaccine in the United States.
Human papillomavirus (HPV) is the most common sexually transmitted infection in the United States, and certain strains are associated with the majority of cancers of the cervix (90%), anus (90%), vagina and vulva (70%), penis (60%), and oropharynx (71%) [
In the internet age, Google searches represent a common approach for discovering information online [
Google Trends (GT) is a popular tool used to analyze online search behavior and search queries in the field of big data analytics in health care and public health research [
To date, several studies have examined HPV vaccine–related misinformation [
We collected monthly search volumes and search queries for the term “HPV vaccine” from GT between January 1, 2010, and December 31, 2021; the GT data retrieval period was from November 1, 2021, to January 31, 2022. GT provides a public database of the proportion of searches of a selected query performed on Google Search, and presents the data as a relative search volume (RSV) in a normalized format. The data can be delineated by specific topics and search terms, time and year, and location. Specific to each search term, the RSV value ranges from 0 (minimal to no interest) to 100 (high popularity) based on the term’s search volume. An RSV value of 100 indicates the maximum search interest for the time and location selected relative to that specific term.
GT enables exploring online searches at different time intervals and retrieval queries for any keywords entered in the Google search engine. Using this technique, we retrieved monthly online search queries and normalized RSVs related to the HPV vaccine across states in the United States. GT allows for queries of both “search terms” and “search topics.” The “search terms” query provides the results for all keywords that fall within the category and the “search topic” query renders the results of a group of terms that share the same concept in any language [
We used the framework described by Mavragani and Ochoa [
We plotted a line chart to describe “HPV vaccine” search trends from January 1, 2010, to December 31, 2021. The annual mean (SD) is used to summarize the online searches for each year between 2010 and 2021. One-way analysis of variance followed by the Tukey posthoc test was performed to identify overall and quarterly differences in HPV vaccine searches in each year between 2010 and 2021. A joinpoint regression analysis was performed for each year to analyze the time trend in the GT data using the Joinpoint Regression program (version 4.9.1.0) developed by the National Cancer Institute [
Human papillomavirus (HPV) vaccine–related relative search volumes (RSVs) on Google Trends from 2010 to 2021 in the United States with the corresponding timeline of Centers for Disease Control and Prevention (CDC) guidelines for HPV vaccine administration.
Quarterly differences in relative search volumes on Google Trends for the term “HPV vaccine” from 2010 to 2021 in the United States.
Year | Relative search volume point estimate, mean (SD) | |||||||
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January 1-March 31 (group 1) | April 1-June 30 (group 2) | July 1-September 30 (group 3) | October 1-December 31 (group 4) |
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|
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2010 | 19.6 (0.5) | 21.0 (2.0) | 22.0 (2.6) | 20.3 (3.7) | 0.463 | .72 | ||
2011 | 23.6 (4.9) | 21.0 (2.6) | 41.0 (31.3) | 40.6 (10.0) | 1.242 | .36 | ||
2012 | 32.0 (2.6) | 27.3 (1.1) | 32.3 (2.1) | 27.3 (6.5) | 1.588 | .27 | ||
2013 | 27.0 (1.7) | 36.3 (17.1 | 43.0 (8.1) | 42.3 (11.9) | 1.306 | .34 | ||
2014 | 36.0 (2.6) | 30.6 (1.5) | 42.3 (5.2) | 30.6 (4.5) | 6.593 | .02b, c | ||
2015 | 35.0 (3.6) | 36.3 (2.5) | 45.6 (8.5) | 35.0 (5.2) | 2.659 | .12 | ||
2016 | 37.6 (3.0) | 39.3 (7.5) | 79.3 (18.8) | 42.0 (7.5) | 9.014 | .005b, c, d | ||
2017 | 42.0 (2.6) | 53.3 (5.5) | 63.0 (11.8) | 42.0 (7.8) | 5.192 | .03c, d | ||
2018 | 49.3 (4.9) | 49.6 (2.0) | 60.0 (8.8) | 54.3 (16.6) | 0.780 | .54 | ||
2019 | 56.6 (5.7) | 67.3 (12.0) | 68.3 (5.0) | 57.0 (7.0) | 1.914 | .21 | ||
2020 | 47.0 (10.4) | 42.0 (16.3) | 62.6 (7.0) | 52.6 (3.2) | 2.166 | .17 | ||
2021 | 54.3 (6.8) | 62.6 (2.3) | 71.0 (11.5) | 55.0 (6.9) | 3.146 | .09 |
aOne-way analysis of variance followed by Tukey posthoc test for multiple comparisons.
bSignificant (
cSignificant (
dSignificant (
“HPV vaccine” relative search volume on Google Trends by US states for each year from 2010 to 2021.
State | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | Mean (SD) |
Alabama | 18.5 | 17.9 | 25.5 | 29.4 | 35.3 | 42 | 35.2 | 32 | 58.6 | 53.9 | 43.3 | 40.1 | 36.0 (12.6) |
Alaska | 11 | 16.9 | 18.2 | 28.9 | 22.2 | 19.2 | 36.7 | 23.8 | 34.9 | 23.9 | 26.8 | 28.8 | 24.3 (7.5) |
Arizona | 22.8 | 19.7 | 45 | 45.3 | 36.4 | 41.7 | 40.7 | 35 | 42.8 | 48.8 | 45.2 | 55.1 | 39.9 (10.2) |
Arkansas | 15.5 | 27.2 | 31.7 | 30.9 | 23 | 35 | 32.1 | 35.7 | 30.2 | 37.7 | 39.9 | 41.2 | 31.7 (7.3) |
California | 57.8 | 26.2 | 70 | 42.8 | 61.3 | 67.8 | 53.4 | 61.8 | 60.3 | 64.5 | 74 | 79.4 | 59.9 (14.3) |
Colorado | 24.7 | 22 | 36.4 | 27.3 | 48.2 | 48.9 | 40.6 | 53.8 | 51.2 | 56.3 | 51.9 | 53 | 42.9 (12.3) |
Connecticut | 25.6 | 23.1 | 36.2 | 32.7 | 31.7 | 50 | 40.6 | 47 | 57.7 | 54.3 | 40 | 45 | 40.3 (11.0) |
Delaware | 8.2 | 20.8 | 15.5 | 20.2 | 19.4 | 24.3 | 19.9 | 28.8 | 25 | 29.7 | 33.3 | 32.6 | 23.1 (7.3) |
District of Columbia | 34.2 | 18.5 | 41.5 | 23.9 | 34.5 | 56.6 | 44.1 | 42.2 | 26.1 | 31.7 | 24.9 | 31.5 | 34.1 (10.6) |
Florida | 57.6 | 26.5 | 60.1 | 49.3 | 67 | 57 | 47 | 49.1 | 38.5 | 60.1 | 63.4 | 53.9 | 52.5 (11.3) |
Georgia | 42.5 | 27.3 | 54.3 | 48.1 | 48 | 41.8 | 50.8 | 52.7 | 52 | 57 | 57.8 | 50.6 | 48.6 (8.3) |
Hawaii | 21.9 | 37.5 | 29.1 | 27.2 | 43 | 32.3 | 32.2 | 34.7 | 39.4 | 33.3 | 40.5 | 34.5 | 33.8 (5.9) |
Idaho | 9.7 | 18.1 | 25.1 | 23.6 | 37.1 | 26.2 | 32.6 | 24.8 | 35.8 | 36.8 | 31.9 | 28.8 | 27.5 (8.1) |
Illinois | 41 | 26.1 | 56 | 41.6 | 39.7 | 56.6 | 48.3 | 50.8 | 51.9 | 59.4 | 33.9 | 60.7 | 47.2 (10.8) |
Indiana | 36.1 | 29.8 | 37.7 | 52.8 | 39.2 | 42.6 | 41 | 43.6 | 43 | 52.5 | 58.5 | 50 | 43.9 (8.2) |
Iowa | 8.4 | 26.3 | 28.1 | 29 | 42.8 | 35 | 44 | 35.9 | 36.1 | 40.1 | 42 | 38.3 | 33.8 (9.9) |
Kansas | 27.1 | 18 | 33.6 | 44.7 | 18.3 | 30.7 | 32.7 | 29 | 49.2 | 41 | 44.7 | 38.3 | 33.9 (10.1) |
Kentucky | 32.2 | 29.3 | 39.5 | 35.8 | 37.3 | 42 | 26.1 | 39.8 | 33.9 | 48.1 | 47 | 38.4 | 37.5 (6.6) |
Louisiana | 28.5 | 18.7 | 40.3 | 38.8 | 41.4 | 36.3 | 38.8 | 33.8 | 57.7 | 50.2 | 47.5 | 53.8 | 40.5 (10.9) |
Maine | 8.6 | 30.1 | 27.2 | 22.2 | 12.4 | 25 | 34.6 | 24.6 | 34.9 | 32.5 | 15.1 | 33.1 | 25.0 (8.9) |
Maryland | 39.1 | 25 | 48.4 | 46.5 | 45.9 | 39.9 | 43 | 35.6 | 43 | 56.7 | 51.6 | 64.5 | 44.9 (10.1) |
Massachusetts | 43.8 | 27.3 | 54.1 | 46.5 | 56.7 | 52.4 | 45.8 | 50.1 | 58.3 | 64.7 | 51.4 | 65.4 | 51.4 (10.2) |
Michigan | 34.4 | 24.3 | 41.2 | 32.8 | 35.9 | 57.5 | 46.7 | 53.5 | 58.2 | 58 | 62.3 | 64.8 | 47.5 (13.4) |
Minnesota | 40.8 | 18.5 | 40.5 | 53 | 50.9 | 38 | 36.5 | 45.7 | 43.3 | 57.6 | 50.6 | 53.7 | 44.1 (10.5) |
Mississippi | 18.2 | 18.5 | 28.7 | 32.5 | 21.1 | 22.4 | 34.7 | 31.1 | 38.6 | 39.4 | 34.1 | 49.3 | 30.7 (9.5) |
Missouri | 40 | 25.3 | 49.4 | 37.9 | 48.2 | 52.7 | 34.4 | 31.7 | 47.6 | 50.9 | 38.1 | 47 | 41.9 (8.6) |
Montana | 11.2 | 17.7 | 24.3 | 20.4 | 20.6 | 20 | 26 | 25.2 | 24.5 | 34.7 | 32.8 | 30.6 | 24.0 (6.6) |
Nebraska | 21.3 | 18.3 | 32 | 39.3 | 33.2 | 26 | 20.3 | 35.4 | 41.4 | 44.5 | 42.1 | 43.7 | 33.1 (9.6) |
Nevada | 21.8 | 14.7 | 29.2 | 35.2 | 38.4 | 39.7 | 38.1 | 39 | 42.3 | 41.5 | 38 | 59.7 | 36.5 (11.2) |
New Hampshire | 19.2 | 15.8 | 31 | 29.4 | 25.4 | 30 | 28 | 28.5 | 35 | 40 | 28 | 31.5 | 28.5 (6.4) |
New Jersey | 43.3 | 29.7 | 39.5 | 44.2 | 39 | 58.3 | 47.1 | 48.5 | 46.6 | 51.8 | 44.9 | 59.7 | 46.1 (8.3) |
New Mexico | 24 | 20.7 | 21.6 | 29.9 | 26 | 27.1 | 35.1 | 41.1 | 40.5 | 30.7 | 20.1 | 33.8 | 29.2 (7.3) |
New York | 51.2 | 25.3 | 47.3 | 58.7 | 51.4 | 66.6 | 55.6 | 62.1 | 62.6 | 56.4 | 60.6 | 72.4 | 55.9 (11.9) |
North Carolina | 34.7 | 17.6 | 51.4 | 51.4 | 48.7 | 61.4 | 44.4 | 54.3 | 56.7 | 54 | 53.8 | 61.6 | 49.2 (12.3) |
North Dakota | 9.5 | 22.7 | 25.1 | 18.4 | 17 | 26.7 | 25.3 | 24.6 | 30.2 | 29.1 | 21.2 | 23.9 | 22.8 (5.7) |
Ohio | 43.5 | 24.4 | 52.4 | 33 | 41.2 | 38.6 | 40.7 | 44.2 | 58.4 | 57.6 | 54.6 | 55.5 | 45.3 (10.6) |
Oklahoma | 23.2 | 14.6 | 37.5 | 39.5 | 39.7 | 46.6 | 43 | 34.2 | 50.5 | 41.1 | 38.9 | 43 | 37.7 (9.9) |
Oregon | 21.6 | 31.7 | 38.5 | 31.2 | 48.4 | 38.2 | 33.5 | 54.9 | 29.7 | 50.8 | 43.6 | 40.5 | 38.6 (9.7) |
Pennsylvania | 50.1 | 35 | 53.4 | 24.9 | 43.2 | 52.9 | 46.1 | 55.2 | 51.1 | 69.3 | 61.4 | 69.8 | 51.0 (13.0) |
Rhode Island | 21 | 18 | 28.7 | 22 | 21 | 10.8 | 37.9 | 27.3 | 30.3 | 39.5 | 37.4 | 32 | 27.2 (8.9) |
South Carolina | 19.9 | 32.3 | 39.3 | 47 | 39.3 | 37.7 | 31.4 | 43.7 | 43.2 | 45.3 | 50.6 | 53 | 40.2 (9.2) |
South Dakota | 12 | 16.7 | 23.6 | 14.7 | 20.5 | 16.4 | 25.8 | 28.1 | 31.4 | 26.1 | 27.5 | 26 | 22.4 (6.2) |
Tennessee | 27.6 | 26.3 | 35.2 | 41.4 | 46.9 | 33.4 | 42.8 | 39.2 | 50.5 | 52.2 | 49.7 | 58 | 41.9 (10.0) |
Texas | 55 | 22.1 | 52.7 | 55.2 | 51.2 | 63.8 | 50 | 52.5 | 65 | 53.6 | 60.5 | 61.5 | 53.6 (11.1) |
Utah | 31.4 | 25.2 | 36.3 | 28.8 | 31 | 33 | 32.8 | 41 | 21 | 46.1 | 49.3 | 48.3 | 35.4 (9.1) |
Vermont | 12.6 | 15.6 | 15.1 | 23.3 | 22.1 | 25.3 | 21.3 | 27.8 | 24.9 | 16.6 | 16.7 | 33.8 | 21.3 (6.2) |
Virginia | 59.1 | 25.8 | 61.5 | 43.4 | 30 | 38.2 | 44.8 | 55.1 | 58.8 | 59.3 | 58.9 | 62.8 | 49.8 (12.9) |
Washington | 40 | 16.7 | 53.3 | 41.3 | 47.6 | 51.1 | 37.7 | 54.7 | 56 | 64 | 51.4 | 57.9 | 47.6 (12.5) |
West Virginia | 12.8 | 26.1 | 16.8 | 29.8 | 33.9 | 23.1 | 29 | 29.3 | 43.8 | 41.5 | 33.7 | 39.4 | 29.9 (9.4) |
Wisconsin | 31.4 | 28.7 | 44.7 | 47 | 20.8 | 45.1 | 42.4 | 39.8 | 55.3 | 44.3 | 44.2 | 62.2 | 42.2 (11.2) |
Wyoming | 9.5 | 7.9 | 3.5 | 17.3 | 14 | 22.2 | 13.5 | 13.9 | 25.4 | 31.5 | 26.7 | 23.5 | 17.4 (8.5) |
The joinpoint regression plots are provided in
Two joinpoints were noted in 2014, 2016, and 2020, all demonstrating similar patterns: a decrease in search interest early in the year, followed by an increase from April/May to August, and finishing with a decrease through December. Specifically, in 2014, there was a significant increase in the RSVs by 17.8% (
To explore annual temporal changes in trends in HPV vaccine RSVs in the United States from 2010 to 2021, we estimated the APCs using joinpoint regression analysis and fit three models, allowing for no joinpoints, one joinpoint, and two joinpoints, respectively (
Joinpoint regression analysis indicating trends in "HPV vaccine" relative search volume (RSV) on Google Trends from 2010 to 2021 in the United States. Monthly percentage changes (MPCs) in the HPV vaccine RSVs are described in Table 2. The number of slopes is determined by the number of joinpoints identified by the analysis. Joinpoints are the time points when statistically significant changes in the linear slopes are noted.
Monthly percentage changes (MPCs) in the “HPV vaccine” relative search volumes (RSVs) corresponding to the regression graphs (a–i) in
Regression graph in |
Year | Specified monthly perioda | MPC in RSVsb |
a | 2011 | 1-12 | 7.80 |
b | 2013 | 1-12 | 5.13 |
c | 2014 | 1-5 | 7.50 |
c | 2014 | 5-8 | 17.77 |
c | 2014 | 8-12 | –13.12 |
d | 2016 | 4-7 | 40.73 |
d | 2016 | 7-12 | –16.14 |
e | 2017 | 1-8 | 8.05 |
e | 2017 | 8-12 | –15.44 |
f | 2018 | 1-10 | 3.91 |
f | 2018 | 10-12 | –21.73 |
g | 2019 | 1-7 | 6.13 |
g | 2019 | 7-12 | –6.99 |
h | 2020 | 1-4 | –20.04 |
i | 2021 | 1-8 | 5.51 |
i | 2021 | 8-12 | –10.05 |
aNonsignificant monthly periods are not displayed.
bThe MPC is significantly different from 0 at α=.05 in all periods.
Joinpoint regression analysis showing changes in “HPV vaccine” relative search volume on Google Trends over time in the United States.
Segment | Period | Change year | Annual percentage change (95% CI) | ||
Model 1a | 2010-2021 | None | 8.6 (5.9 to 11.4) | 7.2 | <.001 |
Model 2 | 2010-2018 | 2018 | 11.6 (7.3 to 16.1) | 6.6 | <.001 |
Model 2 | 2018-2021 | 2021 | –2.2 (–18.4 to 17.2) | –0.3 | .78 |
Model 3 | 2010-2012 | 2012 | 17.9 (–16.8 to 67.0) | 1.3 | .26 |
Model 3 | 2012-2018 | 2018 | 10.3 (2.0 to 19.3) | 3.5 | .03 |
Model 3 | 2018-2021 | 2021 | –1.3 (–17.1 to 17.5) | –0.2 | .85 |
aFinal selected model, best fitting based on the permutation method.
b
To our knowledge, this is one of the first studies to examine US public online searches regarding the HPV vaccine using GT data. In analyzing the data on HPV vaccine–related online searches in the period from January 2010 to December 2021, we identified important trends, including an overall increase in online searches with noticeable spikes corresponding to key changes in vaccine recommendations. Overall, the joinpoint regression showed a significant average annual percentage increase of 8.6% in HPV vaccine search interest from 2012 to 2021, along with various time trends in HPV vaccine searches across years as well as within years. At the state level, the 12-year average annual HPV vaccine search interest in the United States was the greatest in California (59.9, SD 14.3), New York (55.9, SD 11.9), and Texas (53.6, SD 11.1), while Wyoming (17.4, SD 8.5) recorded the lowest interest in HPV vaccine searches.
Although previous studies in the United States have explored the influence of social media on HPV vaccine communication [
By using joinpoint regression, we found significant variation in the HPV vaccine RSVs trend by month and year. In nearly every year (8 out of 12), we saw a similar pattern with a significant rise in searches (ie, RSVs) leading up to July and August, followed by a drop in searches, suggesting that HPV vaccine interest was short-lived. This pattern of RSV peaks in July/August syncs with the annual school calendar and the back-to-school period. This is worth noting, as many states and school districts continue to weigh the benefits and costs of vaccine mandates, and whether the HPV vaccine will be required for school attendance [
HPV vaccine searches differed by US states and demonstrated wide variations in year-over-year searches. All of the US states showed a positive trend in annual HPV vaccine searches from 2010 to 2021; however, some states such as Delaware (mean 23.1, SD 7.3), North Dakota (mean 22.8, SD 6.2), South Dakota (mean 22.4, SD 6.2), Vermont (mean 21.3, SD 6.2), and Wyoming (mean 17.4, SD 8.5) recorded lower RSVs. Although the underlying reasons for these differences are not clear, the changing trend in HPV vaccine searches indicates a positive impact on health-seeking behavior. In this regard, information technology interventions may consider targeting states with lower search volumes to raise awareness, or, alternatively, targeting states with higher search volumes to provide resources for action. Overall, targeted health education materials are needed to ensure that accurate, reliable, and updated information on the HPV vaccine is available online for parents, caregivers, adolescents, and young adults.
Our study identified variations in HPV vaccine search volume by time and geography. These findings could be used to inform targeted search engine advertisements that describe the benefits of the HPV vaccine and how it can prevent cancers, tailoring to different times, geographies, and topics. This approach builds upon prior work using Google Ads to deliver health education materials based on keyword searches [
This study has several limitations. First, GT data are observational data; therefore, making causal inferences (eg, more HPV vaccine searching leads to greater HPV vaccine coverage) is not possible. However, we can use these infodemiology data, demonstrating variation in online searches by time and topic, to tailor health education and promotion materials related to HPV vaccination. These materials may be made available online and even targeted as search engine advertisements during periods of high search volume. Second, our study’s units of analysis were at the national and state levels. While these data provide overall indicators for online searches and vaccine coverage, they do not capture the relationship that may be present at other levels of analysis, such as at the community or county level. Third, we are unable to determine the true causes behind changes in search volume; that is, we do not know exactly what prompted increases or declines in searches, but we are able to surmise potential associations based on known federal guideline changes and other information. Fourth, our findings are biased in that they only represent individuals who have internet access and who use Google as their search engine. While most internet users use Google as their search engine (90%) [
This study supports the growing body of work examining online and other digital data, and their application to health care and public health research. Specific to the HPV vaccine, we examined GT data to document online search trends from 2010 to 2021. Our observational findings can be used to inform online intervention points such as event-based opportunities (ie, back-to-school night) and state-specific programs. Notably, we observed a marked decline in online searches during the start of the 2020 COVID-19 pandemic. Further investigation is needed to understand whether the significant factors and variations observed in our study hold to HPV vaccination trends outside of the United States.
Advisory Committee on Immunization Practices
annual percentage change
Google Trends
human papillomavirus
monthly percentage change
relative search volume
Conceptualization, ASB and PM; methodology, ASB and PM; software, ASB; validation, ASB and PM; formal analysis, ASB; writing—original draft preparation, ASB; writing—review and editing, PM; visualization, ASB; supervision, PM. All authors have read and agreed to the published version of the manuscript.
None declared.