Updated

The first batch of H1N1 vaccine is on schedule to arrive in the U.S. in mid-October, but the majority of Americans will not be fully immunized against the disease until Thanksgiving, Human Services Secretary Kathleen Sebelius said Monday.

Not all of the vaccine will be ready for mid-October, however.

“We always knew that not all of the vaccine would be ready at the same time, it’s coming from five different manufacturers,” Sebelius said during an afternoon news conference.

Sebelius said it will take until Thanksgiving to fully immunize people against H1N1 because most will need to undergo two vaccinations. The first would be given in mid-October; the second would be administered three weeks later and it takes about two weeks after the second shot to build up full immunity to the virus.

In the meantime, Americans, businesses, public schools and colleges must find ways to minimize the spread of the virus.

Sebelius said businesses of hourly employees should encourage workers to stay home -- even if it means losing a day's pay -- and not spread the virus. Schools should encourage sick children to stay home and colleges should find ways to isolate sick students (especially those who are far from home) from dorms and cafeterias.

Schools should also consider "online learning opportunities in the event the disease continues to transmit and schools have to look at closing." she said.