Swine flu infections in the United States will be past their peak when (A)H1N1 vaccine becomes readily available, a top health official said Wednesday.

"It is likely that the current wave of infection will peak, crest and begin to decline before there are ample supplies," Thomas Frieden, director of the Center for Disease Control and Prevention (CDC) told lawmakers at a briefing.

"Currently we are continuing to see virus activity and the number of people getting sick increase in many states, although it has already begun to decrease in other states, particularly in the southeast," Frieden said.

"Whether there will be another wave of H1N1 between now and May when the flu season ends or whether we'll get another strain of influenza, only time will tell," he told the briefing called to address a serious shortage of vaccine in the United States.

Nicole Kunka, a staff member of the House Appropriations Subcommittee on Labor, Health and Human Services, said the government had fallen "miserably short" of its H1N1 vaccine production goal.

"Initial government estimates were that 160 million doses would be available by October... on October 29, 24.8 million doses were available," she said.

Kunka cited statistics from the Department of Health and Human Services which "indicate that doses sufficient to cover all priority populations will likely not be available before January 2010."

The vaccine shortfall has seen long lines forming outside health clinics, with many people in the five priority groups for inoculation being turned away or going home without getting their swine flu shot as vaccine supplies ran dry.

Children and pregnant women have been particularly hard hit by the swine flu pandemic. Other priority groups include health care workers, people with chronic health conditions such as asthma, and childcare workers who cannot themselves be vaccinated.

More than 5,700 people have died worldwide since the virus was first discovered in April, with most of the deaths -- 4,175 -- in the Americas region, the World Health Organization said Friday.