<a href="https://bmjopen.bmj.com/content/13/6/e065687" target="_blank" rel="noopener nofollow">https://bmjopen.bmj.com/content/13/6/e065687</a><br><a href="https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2021-06/03-COVID-Shimabukuro-508.pdf" target="_blank" rel="noopener nofollow">https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2021-06/03-COVID-Shimabukuro-508.pdf</a>