Google, Facebook and others in a hurry to prevent the dissemination of anti-vax information

The American Medical Association urges major social media and technology companies, including Amazon, Facebook and Google, to fight the spread of misinformation about vaccinations on their platforms.

The country's largest medical group on Wednesday sent a letter to Amazon, Facebook, Google, Pinterest, Twitter and YouTube executives, in which it was troubled by reports of anti-vaccine messages and ads targeting parents looking for vaccine information. AMA said it was particularly worrying at a time when vaccine-preventable diseases, such as measles, are increasing in the United States, posing a threat to public health.

AMA has expressed concern that misleading health information discovered online will jeopardize science and do not persuade parents to avoid vaccinating their children, which would trigger the spread of preventable diseases.

"Since public health is online and social media is the main source of information for the American people, we invite you to do your part so that users have access to scientifically valid information about vaccinations, so that they can make informed decisions regarding the health of their families, "said in his letter the director general of WADA, James Madara.

"We also invite you to make your projects public to ensure that users have access to accurate, timely and scientifically reliable information on vaccines," he wrote.

The letter comes as lawmakers, activists and health experts put pressure on companies to prevent viral anti-vax disinformation. Misinformation may have contributed to a measles epidemic in the United States.

Facebook said last week that it is stepping up its efforts to curb the spread of misinformation on vaccines, claiming that this would lower the ranking of groups or pages that spread misinformation about vaccines in its news feed and in search results.

Other tech companies have also stepped up their efforts to fight misinformation about vaccines. Pinterest blocked anti-vaccination research and tried to reduce the anti-vax content. In February, Youtube said it would remove ads from videos featuring anti-vaccination content.

None of the companies mentioned in the letter immediately responded to requests for comments on the WADA letter.

Queenie Wong from CNET contributed to this report.