(Adds comments from Trudeau, WestJet, Air Canada, Moderna , Health Canada; Air Canada stock price; background)
By Steve Scherer and David Ljunggren
OTTAWA, Jan 29 (Reuters) - Canada's major airlines have agreed to suspend all flights to Mexico and the Caribbean for three months starting on Sunday as the country's COVID-19 vaccine rollout suffered another setback, Prime Minister Justin Trudeau said on Friday.
All airline passengers arriving from abroad will also be required to take a mandatory COVID-19 test at the airport and wait in a hotel for up to three days at their own expense until the results arrive, Trudeau said.
"Now is just not the time to be flying," the prime minister told reporters.
Trudeau also said Moderna Inc's MRNA.O next delivery would be almost a quarter smaller than expected. has faced pressure from provincial leaders to tighten restrictions because travelers who returned from spring break trips last year brought the virus with them.
Governments globally are adding new travel restrictions, requirements and bans amid fears over the spread of a more contagious and potentially vaccine-resistant COVID-19 variant first identified in South Africa.
Only four airports will be open for returning international flights - Vancouver, Toronto, Calgary and Montreal. And in coming weeks Canadian vacationers returning from the United States by land will have to show a negative COVID-19 test result before being allowed entry.
WestJet anticipates canceling some 950 flights from Jan. 31 to the end of April, a spokeswoman said. If not for the pandemic, WestJet would have had 6,500 flights to Mexican and Caribbean destinations over that period, she added.
In a statement, Air Canada said it would suspend operations to 15 destinations and added that it appreciated the "collaborative approach" between the government and all air carriers to the pandemic.
Air Canada shares were down 5.3% at C$19.91 at mid-afternoon.
The government has been in talks with airlines about an aid package for almost two months, but nothing has been announced.
On Thursday, Canada reported 4,877 new coronavirus cases, with 19,664 deaths since the start of the pandemic.
Moderna said it would ship 78% of the vaccines it had promised for next week, Trudeau told reporters, adding that the company was still on track to deliver 2 million doses in the first quarter. Pfizer Inc (NYSE:PFE) PFE.N is delivering no vaccines to Canada this week. Friday, Trudeau said he spoke to Pfizer Chief Executive Albert Bourla for the second time in a week and was assured Canada would still receive the promised 4 million doses in the first quarter.
Also on Friday, Health Canada said it would complete its review of AstraZeneca Plc's AZN.L vaccine in the coming days.