Washington, Oct 19 (IANS): Some northern US states are starting to witness a Covid-19 resurgence as the weather is getting colder amid the onset of the winter season, raising concerns over a "twindemic" of the flu and coronavirus.

The five states that are reporting most of the new daily Covid-19 cases per capita are Alaska, Montana, Wyoming, North Dakota and Idaho, Xinhua news agency quoted data by The New York Times published on Monday as saying.

Alaska is logging the highest daily average of 125 cases per 100,000 people.

Meanwhile, the other states with the fastest rising Covid-19 caseloads are Vermont, Colorado, New Hampshire, Michigan and Minnesota, the data revealed.

The country is currently witnessing a downward trend in the pandemic situation, and the wave driven by the Delta variant is also receding.

Though health experts do not expect another catastrophic winter wave like last year, they have warned the public not to let their guard down as a large portion of the population is still unvaccinated, and the flu season may bring complications.

Americans have built up less natural immunity against influenza because so few were infected in 2020, experts say.

As Covid-19 and the flu share many of the same symptoms, such as fever, cough and chills, it will be hard to determine without a test.

"The weather drives people indoors into poorly ventilated spaces, and when either academic activities or social activities occur without masks in indoor, poorly ventilated spaces, that's when transmission occurs," Natasha Bagdasarian, chief medical executive of Michigan said on Monday

The Centers for Disease Control and Prevention (CDC) recommends the public to get flu shots by the end of this month.

The agency has also called on all eligible people, including adolescents ages 12 to 17 years, to get vaccinated to help stop the pandemic.

Anthony Fauci, the nation's top infectious disease expert, said Sunday that even as the most recent pandemic surge wanes, and case and hospitalisation numbers drop, any progress could plateau if vaccination numbers do not improve and the virus continues to circulate.

Till date, 189.1 million people have been fully vaccinated against Covid-19, making up 57 per cent of the entire US population, according to CDC data.

As of Tuesday morning, the country's overall Covid-19 caseload and death toll stood at 45,050,219 and 726,196.