Table 2.

Content of successive samples of YouTube videos about COVID-19 vaccination, July through December 2020.

Content covered	July 2020				December 2020
	Number of videos (n)	Number of views (n)	Percentage of cumulative views (%)	Number of videos (n)		Number of views (n)	Percentage of cumulative views (%)
Vaccine development	77	47,745,687	86.7	93		52,907,010	92.0
Fast-tracking	57	31,891,480	57.9	70		40,140,849	69.8
Emergency use authorization	3	593,609	1.1	22		10,132,084	17.6
Vaccine manufacturing	31	17,498,885	31.8	36		18,817,111	32.7
Vaccine dissemination	17	10,197,203	18.5	27		14,732,085	25.6
Vaccine eligibility	12	5,410,203	9.8	25		9,652,883	16.8
Vaccine dosing	4	2,217,251	4.0	26		9,017,039	15.7
Herd immunity	5	2,286,901	4.2	6		3,173,062	5.5
Adverse reactions to the vaccine	11	6,456,465	11.7	31		15,686,832	27.3
Fear	6	1,449,915	2.6	20		9,553,368	16.6
Concerns about effectiveness	6	5,966,961	10.8	25		12,317,526	21.4
Concerns about immunity duration	5	2,415,092	4.4	10		3,953,045	6.9