One of Canada's premier vaccine centres celebrates its 50th birthday this week, but researchers say it comes amid unease over U.S. policy changes and funding cuts that threaten to upend the global fight against disease.

The search for 5-year-old Darius Macdougall, who went missing while on a camping trip with his family, is in its fourth day, but so far there is no sign of the missing Alberta boy.

The outbreak update says the cases are spread across six provinces, with the majority in Ontario and Quebec, and 16 people are hospitalized.

The report notes that it is in contrast to previous research, which has suggested that moderate and light drinking might even have a protective effect on dementia.

The advisory is the latest pushback on claims raised by U.S. President Donald Trump and his top political health appointees this week linking acetaminophen to autism.

Tylenol's parent company, Kenvue, saw its stock price rebound in premarket trading on Tuesday after U.S. President Donald Trump made unfounded claims about the drug.

U.S. President Donald Trump on Monday used the platform of the presidency to promote unproven ties between Tylenol, vaccines and autism without giving new evidence.

The CDC advisory group recommended against allowing parents to choose the combined measles-mumps-rubella-varicella vaccine before age four.

Only specific groups will continue to be eligible for subsidized vaccines, including people with chronic health conditions, those aged 65 and older, and health-care workers.