Table 3. Types of active involvement of pro-vaccine and anti-vaccine group members.

Type of involvement	Pro-vaccine N	Anti-vaccine N	X2	P
Internet forum	84	58	1.56	.21
Social media	58	37	1.84	.18
Societies	15	36	15.98	< .001
Conferences	15	18	1.38	.24
Discussing with acquaintances	146	101	5.34	.021
Other	2	4	n/a	n/a