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Why Is Flu Season In The Winter

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Tis The Season For The Cold And Flu

Why is flu season in the winter?

Find out when cold and flu season begins, peaks, and ends.

Unless you live in a bubble, chances are you will be exposed to the cold and flu virus. While these contagious viruses can be found year-round in the United States, they are most common during the fall and winter. Cold and flu activity often begins to increase in October.1 You can monitor activity in your area with the Theraflu Cold and Flu Tracker.

Could This Season Be Harder Than Others

Experts have said it is difficult to predict the severity of the flu season in the Northern Hemisphere, but some have warned it could be challenging this year.

Last year, influenza activity was dramatically lower compared with the previous years in both the Southern and Northern Hemispheres.

Due to the far lower number of infections last year, the strains circulating this year may be harder for peoples immune systems to detect, which could leave people more susceptible to infection and may even lead to more severe illness.

Natural immunity wanes, so with little influenza last year, people are more susceptible, Dr Robert Klugman, medical director of employee health at UMass Memorial Health in Worcester told Al Jazeera.

Dr Amesh Adalja, senior scholar at the Johns Hopkins Center for Health Security, said people continue to take precautions against catching or transmitting COVID-19, which could lead to a milder flu season compared with those before the COVID pandemic.

A lot of the people are still doing some of the mitigation measures from COVID-19 that had an impact on flu, like social distancing, wearing masks, being careful when they are in a high-risk setting, said Dr Adalja.

So I do think that flu is going to be more common this season in the Northern Hemisphere than it was last season, but I think it might be a milder season than the ones we had in the pre-COVID era, he added.

Certain Viruses Peak In Winter Months

Diseases such as influenza are seasonal illnesses, Levitan says, explaining that while we can catch the flu all year round, flu activity peaks in the winter. According to Harvard University, one of the main reasons cases of the flu peak in winter is because the virus survives better in colder, drier climates.

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Germs Can Spread In Close Quarters

Many of us tend to hibernate during winter months, and since we are less likely to go outside, we spend more time in confined spaces. Less fresh air means more exposure to sick people, Dr. Levitan says, and indeed, a 2011 study done at Virginia Tech shows that dry, badly ventilated air may increase the spread of the influenza virus. There is also more opportunity for viruses to spread when people are in close contact at school and work.2

Fortunately, there are some ways to try to avoid catching a cold or the flu during winter.

The Fact That It Is Simply Colder In Winter Cant Explain The Yearly Flu Season

Looking good this winter means preventing cold and flu

A new understanding of influenza couldnt come quickly enough worldwide, up to five million people catch the illness each flu season, and around a quarter of a million die from it. Part of its potency comes from the fact that the virus changes so quickly that the body is rarely prepared for the next seasons strain. The antibodies weve built up no longer recognise the virus so we lose our immunity, says Jane Metz at the University of Bristol. It also makes it harder to develop effective vaccines, and although you can engineer a new jab for each strain, governments often fail to persuade enough people to take it up.

Germs can linger for a long time on an underground train

The hope is that by understanding better why flu spreads in winter, but naturally fades in summer, doctors could find simple measures to stop its spread. Previous theories had centred on our behaviour. We spend more time indoors in the winter, meaning that were in closer contact with other people who may be carrying germs. Were more likely to take public transport, for instance and as were pressed against spluttering commuters, misting up the windows with their coughs and sneezes, its easy to see how this could send us over a tipping point that allows flu to spread through a population.

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Eu Health Agency Warns Of Severe Winter Flu Season For Elderly

An elderly man sits at the “Viktualienmarkt” daily food market, during the spread of the coronavirus disease in Munich, Germany, March 18, 2020. REUTERS/Andreas Gebert

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The main reported subtype of the influenza virus seen in the EU and European Economic Area disproportionately affects older people and is associated with lower vaccine effectiveness, the European Centre for Disease Prevention and Control said.

“The early detections of the A subtype are an indication that the upcoming flu season could be severe, although we cannot know for sure what the upcoming flu season will look like,” said Pasi Penttinen, ECDC’s head of influenza programme.

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Penttinen urged health workers to get vaccinated against both COVID-19 and the flu before winter, and added that physical distancing and hygiene measures are important for all, especially those working in nursing homes and healthcare settings.

About 20% of the population catches the flu each year. The elderly, pregnant women and those with chronic medical conditions are most at risk of severe complications by influenza, the ECDC said.

The influenza onset is above the seasonal threshold in Croatia, which is unusually early, given the overall number of influenza detections in the majority of EU/EEA countries remain low, the agency added.

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How Will The Covid Pandemic Affect Flu Season

Experts say Northern Hemisphere countries face an unpredictable winter as COVID continues to spread during the flu season.

Countries in the Northern Hemisphere are facing an unpredictable winter as COVID-19 continues to spread during the flu season, experts have warned.

Last year, when governments recommended a range of protective measures such as mask-wearing, social distancing and lockdowns to slow COVID-19 infections, the number of influenza cases dropped dramatically compared with the seasonal average.

According to the European Centre for Disease Prevention and Control about 20 percent of the population catches the flu each year, but that figure fell by more than 99 percent in 2020-21. There were no hospitalised cases nor fatalities reported from influenza last season.

Cases this year have remained low, according to the World Health Organization , but with COVID restrictions being lifted in many parts of the world, children back in school, and the coronavirus continuing to spread, experts are urging people to remain cautious. An uptick of influenza cases could burden health systems already facing difficulties due to outbreaks of COVID-19.

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How Are Flu Outbreaks Tracked In Minnesota

Public health workers track outbreaks in larger institutions like nursing homes and schools. When people come into certain clinics or laboratories around the state, viruses are forwarded on to the Minnesota Department of Health, said U of Ms Osterholm.

Testing is then performed to determine the type of flu virus circulating. That tracking and testing is used to make recommendations to the public about their flu shots, he said.

Study Shows Why The Flu Likes Winter

Why The Flu Season This Winter Was Virtually Nonexistent | All In | MSNBC
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By Gina Kolata

Researchers in New York believe they have solved one of the great mysteries of the flu: Why does the infection spread primarily in the winter months?

The answer, they say, has to do with the virus itself. It is more stable and stays in the air longer when air is cold and dry, the exact conditions for much of the flu season.

Influenza virus is more likely to be transmitted during winter on the way to the subway than in a warm room, said Peter Palese, a flu researcher who is professor and chairman of the microbiology department at Mount Sinai School of Medicine in New York and the lead author of the flu study.

Dr. Palese published details of his findings in the Oct. 19 issue of PLoS Pathogens. The crucial hint that allowed him to do his study came from a paper published in the aftermath of the 1918 flu pandemic, when doctors were puzzling over why and how the virus had spread so quickly and been so deadly.

As long as flu has been recognized, people have asked, Why winter? The very name, influenza, is an Italian word that some historians proposed, originated in the mid-18th century as influenza di freddo, or influence of the cold.

Flu season in northern latitudes is from November to March, the coldest months. In southern latitudes, it is from May until September. In the tropics, there is not much flu at all and no real flu season.

We needed some actual data, Dr. McCullers added.

But getting data was surprisingly difficult, Dr. Palese said.

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Protecting Yourself From The Flu

As you enter your golden years, it becomes critically important to protect yourself from the flu. Adults age 65 and older are at risk for complications associated with the flu, as are people with some long-term health conditions like diabetes or heart disease. People who live in long-term care facilities like retirement homes are also at higher risk of contracting the illness. Your first step to protect yourself from the flu is to get a flu vaccine each year. If you dont get the vaccine by the beginning of flu season, its not necessarily too late. During flu season, you should also stay away from people who are sick with the flu and wash your hands often with soap and water or an alcohol-based hand sanitizer. Finally, try to avoid touching your nose, mouth, or eyes. Touching your face can leave you vulnerable to germs.


So, why is flu season in winter? The combination of cold temperatures, shorter days, and lots of time spent indoors can lead to a worrisome number of flu cases. Flu season can be especially serious for people in their golden years, so if you havent already gotten your flu shot, remember that its not too late.

Were In Such Unusual Circumstances That Its Extremely Difficult To Predict What The Flu Situation Will Be Like This Year Says Tiley

But I think theres a realistic chance it will be very bad either this winter or next because of waning herd immunity, he adds. I think 2022 is more likely to be a problem year because the virus has more time to bounce back.

Immunity due to infection or vaccination against flu wanes over time. Initially the level of immunity can be high enough to prevent reinfection. However, as this immunity wanes , it becomes quite likely that you can be re-infected, even by exactly the same strain that you may have been vaccinated against previously.

In a normal year, reinfection with the same strain of flu would helpfully top up your immunity. But in the past two years there has been a lot less of this topping up going on because of COVID lockdowns and social distancing, so I think immunity will have waned in more people and to a greater degree, says Tiley.

We expect that the severity of flu caused by reinfection would be low – your secondary immune response kicks in quickly to prevent you becoming appreciably sick, unless of course the virus has evolved significantly in the meantime, he says. Nevertheless, by that stage the virus will have replicated in your respiratory tract to a level where it can be successfully passed on to someone else.

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Why Flu Season Strikes In Winter

In United States, the influenza virus spreads roughly from October to April, according to the U.S. Centers for Disease Control and Prevention. In Australia, the flu season is more like May to October the Australian winter.

In fact, everywhere that experiences a winter, theres a flu season.

So whats the connection?

Its not because being cold gives you a cold, as your grandmother might have you believe. There are several existing hypotheses, though why flu flourishes in the winter is a fascinating question thats engaged infectious disease doctors and virologists for years, Dr. William Schaffner, the immediate past-president of the National Foundation of Infectious Diseases and professor of preventive medicine at the Vanderbilt University School of Medicine, told

The top theory: There’s something specific about the influenza virus that enables it to flourish in cold, dry weather, Dr. Schaffner said.

Cooler air and lower humidity promote the transmission of the influenza virus from one person to another, he said.

A study from the National Institute of Child Health and Human Development found that the virus forms a special outer coating in cold weather that helps it fly through the air and into another person. Flu is an airborne illness that can be transmitted to another person from as far as six feet, according to the NIH. This cold-weather coating simply helps along this process.

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How To Reduce Your Chance Of Infection

How To Survive The Winter Flu Season

Getting vaccinated for the flu and vaccinated and boosted for COVID-19 are your best protection against serious illness and hospitalization. While Omicron infections mimic the cold in many vaccinated/boosted people, others have been hit far harder. This is especially true among the unvaccinated. According to recent research from the Centers for Disease Control and Prevention , unvaccinated people are 20 times more likely to die from COVID-19 than fully vaccinated people with boosters or additional doses.

Of course, continuing additional precautions helps protect against infections:

  • Wear a mask. Masks are a simple, effective way to shield yourself and others from spreading viruses through respiratory droplets.
  • Practice social distancing. Stay at least 6 feet from others.
  • Wash your hands regularly. Frequent handwashing can help protect against many infections, including the flu and common cold.
  • Avoid touching your eyes, nose and mouth. Keeping your hands away from your face reduces your risk of germs entering your body.

Remember that its not too late to get your annual flu shot or COVID-19 vaccine. To find out where to get a COVID-19 vaccination or booster near you, visit the New Jersey COVID-19 Information Hub.

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Baylor College Of Medicine Blog Network

This time last year, headlines warned of a twindemic a wave of influenza occurring at the same time as an uptick in COVID-19.

But it didnt happen.

Flu outlook looks more severe

The 2020-21 flu season was considered unusually low in the U.S. and globally, according to the Centers for Disease Control and Prevention. Between September 2020 and May 2021, only 1,600 out of 820,000 respiratory specimens were positive for an influenza strain nationwide.

Do not expect another easy flu season this year, said Dr. Stacey Rose, assistant professor of infectious diseases at Baylor College of Medicine.

This year has the potential for increased respiratory illnesses across the country because of fewer masks, relaxed restrictions and holiday gatherings with friends and families, she said.

Folks are traveling were different from where we were last year. You see it in commercials this is the year where everyone wants to be back together, Rose said. No one in the commercials is wearing masks.

During the summer, Texas children experienced an untimely surge in respiratory syncytial virus , which resulted in multiple hospitalizations. While RSV is less contagious than COVID and flu, Rose said that virus spread could be indicative of what the city may experience with respiratory illnesses in colder months.

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Influenza Is Constantly Exploring Ways To Escape Population Immunity Says Gog

To do this it needs to have lots of cases, so that there is enough opportunity to generate mutations,” she adds. “If it succeeds, it can then cause lots more cases. Its almost like the lottery – to win you need to buy lots of tickets.

Putting their 2004 results into todays context suggests that COVID-19 might have actually driven flu into a downward spiral – reducing the overall number of flu cases so much that the chance of new variants being produced is also dramatically reduced.

Im not yet at all convinced by the arguments out there that 2021 is going to be a super bad year for influenza, says Gog. And she has another theory about flu thats an even greater cause for optimism. She thinks that recent COVID restrictions might have forced flu into a rut it may be stuck in for some time.

Influenza probably isnt free to mutate and evade our immunity without having to make some compensatory changes – and these could temporarily weaken it. So when theres a lot of immunity, the virus could get stuck in this intermediate phase as it cant generate enough cases to get going again, or at very least it will take several years before it gets lucky.

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Ways To Prepare For Cold And Flu Season

  • Consider getting a flu shot because the CDC says it reduces the risk of getting sick by 50%
  • Wash your hands frequently as germs can live on everything you touch. Washing your hands, and using hand sanitizer in the moments where you cant clean your hands will lower your risk of getting a cold or flu.
  • Minimize contact with sick people and keep your distance from those coughing or sneezing
  • Keep an eye on the activity in your area with the Theraflu Cold and Flu Tracker
  • Consult with your doctor about which flu vaccine is best for you.For the 2021 cold and flu season, there are three main flu vaccines availableIIV, RIV4, and LAIV4.2 If you consult with the physician or pharmacist thats administering your vaccine, there are additional options for vaccines with a higher dosage, egg-free vaccines, and even a vaccine that is given through nasal spray.2
  • Check the Centers for Disease Control and Prevention for the latest strains of the flu in your area.The flu virus can change constantly and without notice. Your local health care facility might also be able to provide any updated information on new strains of vaccines as well as any increases or decreases on how its spreading in your area.
  • Eat healthy and stay hydratedA healthy diet can lower your risks of getting sick in the winter. Staying hydrated can reduce congestion in your nose and chest. Getting the proper nutrients can strengthen your immune system as well.
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