The Centers for Disease Control is encouraging people in flu vaccine priority groups to get vaccinated in light of findings that flu activity does not appear to have peaked yet.

The agency said flu activity has risen steadily in the United States since mid-December and noted that viruses may continue to circulate for several more months.

Both inactivated flu vaccine and nasal spray vaccine are generally available, though supplies vary by area. The CDC also said an inactivated flu vaccine produced by GlaxoSmithKline for use in Europe will become available later this month at clinics in areas of the United States where the need for vaccine persists.

Once clinics are identified, information on their location will be available through local and state public health authorities by calling the CDC flu hotline at (800) 232-4636.