In total there were 10,946 tweets by 6,264 tweeters, with 53,124 retweets by 32,445 retweeters during the 8 day period studied (noon on 23/4/2020 until noon on 1/5/2020, providing global coverage for the full week of the campaign). Individual retweet data was obtained for 47,300 retweets (the remainder were either not available via the Twitter API or were retweeted in the period between data extraction and the processing by NodeXL (commenced at midnight on 2 May 2020)). Using this dataset a total of 37,551 accounts tweeted and/or retweeted, with 1,158 doing both. Overall, 166 accounts (2.7% of the total tweeters) received 80% of retweets while 4,135 accounts (66.0% of tweeters) received no retweets. 
The tweeters and content were explored using an approach selected for speed and reproducibility. Selecting the most retweeted posts provides a quick view of the most popular and/or controversial material. The top 200 tweets were identified, each of which had received at least 36 retweets by the point of the NodeXL extract (median 78 retweets, interquartile range 49-137), and were posted by 100 organisations or individuals with a median of 102,057 followers (IQR 27,669-372,458). Just 5 of the top 200 posts were clearly antivaccination tweets, posted from 4 accounts. There were no tweets in the top 200 posts that expressed views related to vaccine hesitancy. 
COVID-19 related terms featured in 88/200 of the top posts. These most popular tweets used a range of hashtags: 158 used #VaccinesWork, 63 used #WorldImmunizationWeek or related terms, and 5 had no hashtag. These posts covered a wide range of topics related to the development, testing, delivery, rationale and impact of vaccination programmes, with material tailored for different countries and age groups, with additional messages related to animal vaccination. Some tweets referenced the wide range of infectious diseases and related medical conditions against which vaccination provides protection. Other tweets provided details about the success of vaccination in protecting against specific pathogens including polio and smallpox. They also addressed antivaccination myths in clear and accessible language. Tweets relating to COVID-19 explained the impact of the pandemic lockdown on routine vaccine delivery to key age groups, the ongoing efforts in developing a COVID-19 vaccine, and the place that this might take in the pandemic response. For many of the tweets, for both routine vaccination and a future COVID-19 vaccine, the focus was on vaccination for all. 
The hashtags from all tweets in the extract are displayed in the word cloud below.

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