COVID-19 was announced as pandemic by WHO on 11 Mar [1] , being the only pandemic in the past 10 years (the last one was 2009 swing flu), it was first detected as an unknown pneumonia in Wuhan (Hubei, China). On April 1st, 2020, John Hopkins University Coronavirus Resource Center [2] , reported that the ongoing epidemic has infected 938,373 people, the death toll has already reached 47,272, given the highly contagious nature of the virus as well as the significant mortality rate, numerous governments have announced national lockdown. The impact of COVID-19 on world economy and politics is unprecedented in modern time.
On the past Ebola epidemic crisis, scholars found the importance of using Twitter data to do social science research [3] , [4] , many of them use this microblog data as social indicators to analyze the effect of epidemic outbreak on public concerns [5] , health information needs and health seeking behavior [6] , and public response to policy makers [7] etc. Current open access COVID-19 Twitter data were mainly collected by keywords, such as coronavirus, Covid-19 etc [8] , [9] , none of the them is dedicated to government/news media tweet collection. Given that our retrieval targets are policy makers and news source, we believe our dataset can provide scholars more valuable data to conduct social science research in related fields, such as crisis communication, public relation etc.
We used Twitter REST API to retrieve twitter data from March 12, 2020, there are 8 collection categories: "gov tweet" (governments, international organizations etc.), "US news tweet", "UK news tweet", "Spain news tweet", "Germany news tweet", "France news tweet", "China news tweet" and "Additional news tweet" (news source added later), each of them contains various collection target (twitter account name, details see next section).
At the first time we collected the most recent 3200 tweets of every collection target before March 12, 2020, we didn't set a time limit, which implies that the date of the first tweet from each of the sources may vary and even be relatively old. We update our dataset every week (last update on April 2, 2020), after removing duplicated data by matching tweet id, we get the clean version data.
On the other hand, due to the data collection strategy we made, there may be tweets both related and unrelated to COVID-19, which opens up new possibilities for academic analysis.
Gov tweet category contains the following accounts (Table1): 
The dataset is available on Github at the following address:
https://github.com/narcisoyu/Institional-and-news-media-tweet-dataset-for-COVID-19social-science-research. Our data was collected in compliance with Twitter's official developer agreement and policy [10] . The dataset will be updated weekly, interested researchers will need to agree upon the terms of usage dictated by the chosen license.
Following Twitter official policies, we released and stored only tweet ids, as far as we know, two tools can be used to hydrate full information: Hydrator (https://github.com/DocNow/hydrator) and Twarc (https://github.com/DocNow/twarc).
Interested researchers shall follow the usage instructions of the fore-mentioned tools.