Researchers point to a worrying imbalance.

Facebook communities that distrust establishment health advice are more effective than government agencies and other reliable groups at reaching and engaging with undecided individuals, according to a study published in the journal Nature.
US researchers tracked vaccine conversations among 100 million Facebook users at the height of the 2019 measles outbreak and created a “battleground” map they say shows how such distrust could spread.
“Its core reveals a multi-sided landscape of unprecedented intricacy that involves nearly 100 million individuals partitioned into highly dynamic, interconnected clusters across cities, countries, continents and languages,” they write.