Google COVID-19 Vaccination Search Insights: Anonymization Process Description (version 1.0) Shailesh Bavadekar, Adam Boulanger, John Davis, Damien Desfontaines, Evgeniy Gabrilovich, Krishna Gadepalli, Badih Ghazi, Tague Griffith, Jai Gupta, Chaitanya Kamath, Dennis Kraft, Ravi Kumar, Akim Kumok, Yael Mayer, Pasin Manurangsi, Arti Patankar, Irippuge Milinda Perera, Chris Scott, Tomer Shekel, Benjamin Miller, Karen Smith, Charlotte Stanton, Mimi Sun, Mark Young, and Gregory Wellenius covid-19-search-trends-feedback@google.com July 1, 2021 Abstract This report describes the aggregation and anonymization process applied to the COVID-19 Vacci- nation Search Insights [1], a publicly available dataset showing aggregated and anonymized trends in Google searches related to COVID-19 vaccination. The applied anonymization techniques protect every user’s daily search activity related to COVID-19 vaccinations with (ε, δ)-differential privacy for ε =2.19 and δ = 10 -5 . 1 Introduction The COVID-19 Vaccination Search Insights is a publicly available dashboard [1] and dataset [2] that shows aggregated, anonymized trends in Google searches related to COVID-19 Vaccination. The data provides a weekly time series for each region showing the relative volume of searches across 3 categories: • COVID-19 Vaccination: All searches related to COVID-19 vaccination, indicating overall search interest in the topic. • Vaccination Intent: Searches related to eligibility, availability, and accessibility of vaccines. • Safety and Side Effects: Searches related to the safety and side effects of the vaccines. We are making this data available because we have heard from public health organizations and researchers that they want access to localized and timely data about what information their communities are seeking, so they can better understand the vaccination needs of their communities and tailor their communication to people not yet vaccinated. To ensure strict privacy standards, all published data is aggregated and anonymized, protecting each user’s search activity on a given day using a differentially private mechanism. No personal data is included in the dataset. The Vaccination Search Insights data reflect the (normalized) volume of Google searches that may be associated with a particular COVID-19 vaccination search topic. For this purpose, we count the weekly number of searches relating to that topic within a given geographic region, and normalize this number based on the total search activity in that region. The resulting data is a weekly series showing the relative frequency of searches for that particular topic in a particular region. The data covers the recent period and we plan to gradually expand its range as part of regular updates. Similar to the Google COVID-19 Community Mobility Reports [3] and Symptom Search Dataset [4], and as explained in greater technical detail below, the anonymization process of the Vaccination Search Insights 1