The President of the Irish Medical Organisation has expressed "serious concern" about the rise of the anti-vaccination movement.
A recent UN report revealed the number of measles cases in Ireland grew by 244% last year - from 25 cases in 2017 to 86 last year.
There have been 48 cases of the disease reported so far this year.
One case of measles could infect up to 18 people.
The HSE advises that the MMR (measles, mumps and rubella) vaccine is the safest and most effective way to protect against it.
IMO President Dr Padraig McGarry said vulnerable parents are being swayed by bogus anti-vax articles shared on social media.
He explained: "We have seen a significant rise in populism across the Western world in recent years, from which Ireland is not immune.
"With that populism has come a blind faith in ludicrous theories that do nothing but cause harm to people.
"The rejection and devaluing of evidence-based medical knowledge will make more people sick and endanger lives.
"It is up to all of us to fight this misinformation at every turn."
He said parents holding back on the MMR vaccine results in children being exposed to the diseases the jab protects against.
Dr McGarry added: "Social media’s dark side is real, and it is important that these lies are challenged swiftly and effectively to protect people around the country.
"It is obvious that in light of this trend, we can no longer take the gains of medicine and science for granted."
Last week, the Government indicated it is considering making vaccines for children mandatory.
Health Minister Simon Harris has written to the Attorney General this week seeking legal advice on the matter.
