By November, the U.S. will have only half the doses of H1N1 swine flu vaccine originally predicted, officials from the Department of Health and Human Services now say.

By Oct. 15, the U.S. now expects to have 45 million doses of the new vaccine on hand. Every week after that, another 20 million doses should roll in until the nation has all 195 million doses it's contracted for from five vaccine makers.

This means that at the end of October, there should be 85 million doses -- just over half the 160 million doses predicted by that date.

There was always an asterisk next to the prediction of 160 million swine flu doses by November. That's because vaccine production is a multi-step process in which a lot can go wrong.

Officials originally felt smug when it turned out that the original H1N1 swine flu vaccine seed strains didn't grow well -- that was included in their prediction.

It seems likely that people will need two doses, given three weeks apart, for protection. That means even those at the front of the vaccine-priority line won't be fully protected until late November, four to six weeks after their first shot.