Vaccine misinformation on social media – topic-based content and sentiment analysis of Polish vaccine-deniers’ comments on Facebook

Figures & data

Table 1. Frequency of content criteria categories among all analyzed comments (n = 4042)

Comments analysis criteria	n	%
Content categories
Pro-vaccination statement or deliberating with anti-vaccination content	1,223	-
Conspiracy theories/search for truth	(795)	(28.2)
Unusual theories: Unique theories about purposes of vaccination (e.g. sterilization)	178	22.4
Profit: Vaccination policies motivated by profit	166	20.9
Rebel doctors: “Enlightened” doctors break away from the medical establishment	104	13.1
Foolish doctors: Doctors are ignorant, fearful of sanctions	86	10.8
Cover-ups: Vaccine information withheld from the public	73	9.2
Protection: Government protects doctors/manufacturers from liability	45	5.7
Informed choices: Encouragement to make educated decisions for oneself/one’s children	36	4.5
Collusion: Vaccine promoters benefit from illnesses caused by vaccines	33	4.2
Privileged knowledge: Presenting information the medical world is unaware of/rejects	33	4.2
Fear-mongering: Dangers of diseases exaggerated to frighten parents	21	2.6
Anti-science: Biomedicine is wrong; other ways of “knowing” (i.e. intuition, instinct)	20	2.5
Misinformation and falsehoods	(560)	(19.9)
Self-referencing: Links/references to anti-vaccination “experts”	240	42.9
No references: No statistics/citations provided to support claims	137	24.5
Falsehoods: Unsupported statements made	128	22.9
Misrepresentations: Sources not used truthfully, false conclusions drawn	55	9.9
Safety and effectiveness	(395)	(14.0)
Underreporting: Vaccine reactions are underreported	91	23.0
Poisons: Vaccines contain poisons/toxins/contaminants	82	20.8
Idiopathic illnesses: Vaccines cause illnesses of unknown origin (e.g. autism, SIDS)	78	19.7
Immunity: Vaccines erode immunity, create only temporary/ineffective immunity	57	14.4
Trivial diseases: Vaccine-preventable diseases are uncommon/not contagious/relatively mild	39	9.9
Simultaneous vaccinations: Multiple vaccines at once increase adverse events	25	6.3
Disease decreases: Disease incidences declined without vaccines (i.e. from improved hygiene)	23	5.8
Civil liberties	(371)	(13.2)
Parental rights: Civil liberties violated by taking away parental choice	148	39.9
Totalitarianism: Vaccine mandates are excessive government control	119	32.1
Monitoring: Vaccine programs harass parents who do not vaccinate	104	28.0
Personal testimonies: Stories about harmed children/personal experiences	(306)	(10.9)
Morality, religion, and ideology	(241)	(8.5)
Immoral acts: Vaccination involves immoral acts (e.g. child experimentation)	206	85.5
Anti-utilitarianism: Universal vaccination sacrifices a few to benefit many	33	13.7
Religious tenets: Vaccination is against God’s will	2	0.8
Alternative medicine	(151)	(5.4)
Alternative treatments: Promoting treatments superior to vaccination (e.g. homeopathy)	71	47.0
“Back to nature”: Promoting “natural” approaches (e.g. children should get diseases naturally)	50	33.1
Products for sale: Promoting alternative products (e.g. vitamins, essential oils)	13	8,6
Critiquing biomedicine: Established medical knowledge is wrong (e.g. germ theory is untrue)	13	8.6
Implied debate: Suggesting debates over if vaccination is effective/necessary	4	2.6

Figure 1. Procedures in building the database of gathered comments

Table 2. Quantitative distribution of comments by theme and gender. The difference between male and female authors in the frequency of comment themes was statistically significant (Chi = 215.633, p < .001). The “other” category, including page admins and the ‘‘undetermined gender’’ was not taken into account because of the low numbers

Arguments	Female author	Male author	Other
No argument	10430	3347	84
Pro-vaccination statement	727 (59,4%)	476 (38,9%)	20 (1,6%)
Conspiracy theories/search for truth	548 (68,9%)	240 (30,2%)	7 (0,9%)
Misinformation and falsehoods	374 (66,8%)	182 (32,5%)	4 (0,7%)
Safety and effectiveness	298 (75,5%)	97 (24,6%)
Civil liberties	282 (76,0%)	89 (24,0%)
Personal testimonies: Stories about harmed children/personal experiences	279 (91,2%)	25 (8,2%)	2 (0,7%)
Morality, religion, and ideology	173 (71,8%)	68 (28,2%)
Alternative medicine	125 (82,8%)	26 (17.2%)

Table 3. Share of individual components depending on arguments in sentiment analysis

argument	number of comments	anger (mean)	anger (maximum)	anger (SD)	happiness (mean)	happiness (maximum)	happiness (SD)
No argument	13861	31%	100%	17%	30%	100%	21%
Alternative medicine	151	33%	80%	16%	29%	82%	16%
Civil liberties	371	43%	97%	17%	19%	69%	11%
Conspiracy theories/search for truth	795	43%	98%	16%	19%	80%	11%
Misinformation and falsehoods	560	32%	100%	17%	25%	100%	15%
Morality, religion, and ideology	241	47%	99%	18%	18%	71%	10%
Personal testimonies: Stories about harmed children/personal experiences	306	46%	85%	16%	20%	64%	11%
Pro-vaccination statement	1223	38%	100%	16%	20%	100%	11%
Safety and effectiveness	395	42%	98%	16%	19%	100%	11%

Figure 2. Mean values for anger and happiness in sentiment analysis by comment category