Estimating the size of “anti-vax” and vaccine hesitant populations in the US, UK, and Canada: comparative latent class modeling of vaccine attitudes

Figures & data

Table 1. Vaccine attitudes by highest-probability assignment latent class. Top panel reports mean scores from a five-point Likert agree-disagree scale for each of the latent classes with each country weighted equally. Higher values reflect more pro-vaccine attitudes with reverse coded items indicated with an asterisk. Bottom panel reports the percentage in each class for each country (percentages should be read horizontally)

	Strongly support	Support w/concerns	Vaccine hesitant	Anti-vax	Measurement error
Getting vaccines is a good way to protect children from disease.	4.93	4.23	3.30	1.98	4.80
Generally I do what my doctor recommends about vaccines.	4.70	3.90	3.09	1.88	4.46
New vaccines are recommended only if they are safe.	4.57	3.85	3.14	2.11	4.53
I am concerned about serious side effects of vaccines.*	3.88	2.73	1.84	1.57	1.85
Some vaccines cause autism in healthy children.*	4.58	3.46	2.70	2.10	2.74
Parents should have the right to refuse vaccines required for schools for any reason.*	4.24	3.14	2.04	1.53	2.18
Vaccinations are one of the most significant achievements in improving public health.	4.88	4.08	3.14	1.76	4.76
Class Membership by Country
USA (n = 4612)	34%	26%	23%	7%	10%
UK (n = 4550)	45%	31%	11%	3%	10%
Canada (n = 4089)	41%	28%	15%	7%	9%

Table 2. Substantive latent class membership by demographics and political orientation

		Strong support	Support w/concerns	Hesitant	Anti-vax
USA
Education	No degree	26.2%	27.0%	28.3%	8.0%
	University degree	50.6%	25.0%	12.8%	4.0%
Age	18–24	38.0%	21.4%	20.5%	8.8%
	25–49	27.1%	24.1%	30.3%	8.4%
	50–64	32.2%	30.2%	22.3%	5.3%
	65 and over	47.1%	28.8%	13.1%	4.0%
Ideology	Very conservative	15.8%	20.6%	28.9%	17.9%
	Conservative	20.9%	34.1%	29.2%	7.5%
	Moderate	32.1%	27.6%	24.4%	5.2%
	Liberal	55.9%	21.5%	13.8%	2.7%
	Very liberal	66.9%	9.0%	9.8%	7.6%
Party	Republican	21.8%	31.2%	28.3%	9.6%
	Independent	19.3%	27.0%	31.9%	10.3%
	Democratic	51.5%	21.8%	14.8%	2.8%
Race/Ethnicity	White	39.9%	26.5%	19.9%	6.4%
	Black	13.2%	24.8%	37.9%	10.0%
	Hispanic	28.5%	29.5%	24.5%	5.0%
	Asian	31.2%	22.7%	18.9%	7.3%
	Other	16.8%	22.8%	43.8%	8.5%
UK
Education	No degree	37.0%	35.1%	12.6%	3.2%
	University degree	61.6%	22.8%	6.3%	2.9%
Age	18–24	48.2%	29.0%	15.3%	2.1%
	25–49	38.4%	31.4%	14.9%	3.7%
	50–64	43.8%	33.3%	9.4%	2.2%
	65 and over	56.3%	28.8%	2.2%	3.4%
Ideology	Right (5)	37.8%	29.3%	11.2%	4.4%
	4	50.0%	31.5%	8.1%	3.5%
	3	37.9%	35.3%	12.3%	3.1%
	2	61.6%	24.2%	6.3%	1.9%
	Left (1)	55.5%	21.8%	9.6%	2.3%
Party	Conservative	48.3%	31.9%	5.6%	2.1%
	Labour	51.6%	28.5%	8.7%	2.1%
	None	29.4%	35.3%	18.6%	4.8%
	Liberal Democrat	57.8%	27.8%	5.9%	1.6%
	Green	63.5%	18.0%	7.5%	4.5%
	Scottish National Party	46.3%	35.1%	9.4%	4.0%
	Brexit/UKIP	21.1%	35.5%	20.1%	4.9%
	Other party/No party	33.3%	34.0%	17.1%	4.8%
Canada
Education	No degree	36.8%	29.5%	17.4%	7.3%
	University degree	52.1%	24.3%	10.2%	4.6%
Age	18–24	42.6%	29.2%	15.0%	5.2%
	25–49	34.2%	27.4%	19.8%	8.4%
	50–64	40.1%	30.4%	14.9%	6.3%
	65 and over	55.8%	25.5%	7.3%	3.8%
Ideology	Right (5)	20.6%	22.5%	25.8%	15.0%
	4	38.5%	26.0%	21.0%	8.2%
	3	35.9%	31.8%	16.0%	6.3%
	2	62.3%	23.3%	6.8%	2.9%
	Left (1)	61.5%	19.0%	8.7%	3.2%
Party	Liberal	53.8%	23.2%	8.3%	2.7%
	Conservative	34.9%	32.6%	19.4%	7.4%
	New Democratic Party	56.3%	22.7%	9.9%	3.5%
	Green	50.3%	26.7%	10.8%	6.2%
	Bloc Québécois	44.2%	31.2%	13.4%	2.9%
	Other party/No party	26.7%	30.4%	21.9%	11.0%

Percentages should be read horizontally, which indicate the percentage of each demographic group in each of the four substantive classes. Totals add to less than a 100% because the measurement error class is not presented.

Figure 1. Support for vaccine mandates by substantive class (4-point Likert scale). The Strong Support and Support with Concerns classes support vaccine mandates dramatically more than the Vaccine Hesitant or Anti-Vax classes.

Figure 2. Belief in COVID-19 conspiracy theories (5-point Likert items) by substantive class. The Anti-Vax and Vaccine Hesitant subscribe to COVID-19 conspiracy theories more than other classes, especially the Strong Support class.

Figure 3. Percentage of each latent class in each COVID safety perception category. Low safety ratings include “not at all safe” or “not very safe.” High safety ratings include “somewhat safe” and “very safe.” Don’t know responses depicted separately. The Strong Support and Support with Concerns classes broadly view COVID-19 vaccines as safe, while the Anti-Vax see them as unsafe. The Vaccine Hesitant are more unsure about COVID-19 vaccine safety.

Figure 4. Percentage of each latent class in each COVID effectiveness perception category. Low effectiveness ratings include “not at all effective” or “not very effective.” High effectiveness ratings include “somewhat effective” and “very effective.” Don’t know responses depicted separately. The Strong Support and Support with Concerns classes broadly view COVID-19 vaccines as effective, while the Anti-Vax see them as ineffective. The Vaccine Hesitant are more unsure about COVID-19 vaccine effectiveness.

Figure 5. Percentage of each latent class in each COVID vaccine uptake intention category. Low likelihood ratings include “not at all likely” or “not very likely.” High likelihood ratings include “somewhat likely,” “very likely,” or “extremely likely.” The small group of respondents who already got the vaccine are in their own category. The Strong Support and Support with Concerns classes largely plan to get vaccinated, and the Anti-Vax do not. The Vaccine Hesitant are more evenly divided.