As this year’s flu season drags on, supplies of influenza vaccines are being depleted in some areas of the country, but health experts are predicting that this should not be a cause for concern.

Flu season struck early this winter, leading to a rapid surge in demand for flu vaccinations in some regions of the country. More than 128 million of the 135 million doses of vaccine expected to be manufactured by various pharmaceutical companies and intended for U.S. distribution have already been shipped by their manufacturers as of Jan. 4, according to the Centers for Disease Control and Prevention. The quantity accounts for more than 95 percent of the nation’s planned supply.

Although some locations are temporarily out of vaccine stock, manufacturers are mobilizing to provide more doses to patients in the country. At Duke, Dr. Chris Woods, associate professor of medicine and infectious disease specialist, encouraged vaccination, but did not express concern over the flu season substantially worsening.

“Our stocks of flu vaccine are pretty good at the moment,” he wrote in an email Sunday. “I continue to encourage people to pursue vaccine, but I think the epidemic has passed.”

Dr. Dennis Clements, chief of primary care pediatrics and a researcher of vaccines and infectious diseases, wrote in an email Monday that the flu season is halfway through now and that the situation will likely improve in the next three or four weeks, unless a different strain begins to spread.

Clements noted that the severity of the flu season fluctuates every few years, and that the last bad year was 2009.

“Flu strains vary every year—changing slightly—but last year’s disease often offers some protection for this year’s flu,” he said. “It takes about four years for there to be enough drift for a large part of the population to be susceptible again.”

The virus may have run its course in some areas of the country, but vaccine manufacturers are still mobilizing to send out their remaining supplies.

“Some regions [of the country] may have peaked, while other parts of the country are still on the upswing,” read a CDC FluView report on the week from Dec. 30 to Jan. 5.

Reacting to “late-season demand,” Michael Szumera, a spokesman for vaccine manufacturer Sanofi Pasteur, told The Washington Post that the company would start shipping vaccines from a small reserve previously intended for international distribution.

GlaxoSmithKline, a manufacturer with a headquarters in Research Triangle Park, is also dipping into a pool of extra vaccines due to the higher U.S. demand, according to a recent GSK release. No additional doses are likely to be made in time for the end of this flu season due to the lengthy manufacturing process, however.