Story highlights
- There have been fewer cases of flu so far this season
- Flu strains detected to date are similar to the ones in the flu shot
- Doctors say anyone who has not had a flu shot should still get one
(CNN)Have you noticed something missing from the news headlines this winter? Those ominous reports that the current flu season is shaping up to be a bad one?
That is because signs so far point to this flu season being a mild one. There were several hundred confirmed cases of flu per week in December, compared with a few thousand per week the previous December, according to the Centers for Disease Control and Prevention flu surveillance system. (This system only detects a fraction of all the flu cases in the country to allow comparison of trends between years.) The later the flu season starts, the more mild it is, usually -- there's just less time that viruses are circulating in the environment that season.
But it is too soon to know what kind of flu season we are in store for, said Dr. Joseph Bresee, chief of epidemiology in the flu division at CDC. Recent years were pretty bad, so this flu season could end up looking good by comparison, or the number of flu cases could catch up with those of previous seasons. The classic scenario is for the first flu cases to start to appear in the United States in October or November, then the pace picks up in January and peaks in February or March.
"It's clear that we are on the uptick now and I expect that will continue for the next few weeks," Bresee said.
Given the likelihood that cases of flu will continue to increase over the next several weeks, Bresee recommends that everyone who hasn't had a flu shot yet get one immediately. Ideally, people receive the vaccine when it is first available in their area, usually in September, but getting it now will still provide weeks to months of protection, he said.
So far, H1N1 and H3N2 strains have been the most commonly detected by the CDC surveillance system, and both strains match those that are in the vaccine. This year, no new mutations have been detected in the common flu viruses.
"It looks like the viruses we are seeing in the U.S. and overseas look very much like the vaccine strains," Bresee said. Although this is reassuring, mutations could still emerge, he added.
As many learn the hard way, it is possible to get the flu after you've had a flu shot.
A good omen for this flu season
Each February, the World Health Organization holds a meeting of flu experts to determine the strains that are most commonly infecting people, a moving target as the virus is constantly mutating and changing how efficiently it spreads. A committee determines the three or four flu strains to include in next year's flu shot based on the meeting's recommendations.
The major concern heading into last year's flu season was that mutations in an H3N2 strain of the virus were detected in circulation after the vaccine had already been made. Although H3N2 was present in the flu shot (at least a dead version of it was), the new mutations could make the virus look different enough that the immune system would not recognize it.
The concern turned out to be founded: The 2014-2015 flu shot only reduced the risk of getting the flu by about 20%, whereas in a good year that rate is closer to 60%.
Photos: 10 winter health myths busted
Some winter wisdom is about as factual as Frosty the Snowman. Problem is, these fictions don't just give you the warm and fuzzies: They can pack on the pounds, stuff up your nose and even increase your risk of cancer. This season, don't let these winter health myths get the best of you.
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Photos: 10 winter health myths busted
Myth: Cold air can make you sick.
It's called the common "cold," but lower temperatures alone won't make you sick. In fact, the exact opposite is true. "Cells that fight infection in body actually increase if you go out into the cold," said Dr. Rachel C. Vreeman, co-author of "Don't Swallow Your Gum! Myths, Half-Truths, and Outright Lies About Your Body and Health." It's your body's way of combating the stress of freezing temps.
Plus, according to the National Institute of Allergy and Infectious Diseases, cold viruses grow best at about 91 degrees; if you're outside in the cold, your nostrils are surely colder than that.
Health.com: 5 most common myths about the common cold
It's called the common "cold," but lower temperatures alone won't make you sick. In fact, the exact opposite is true. "Cells that fight infection in body actually increase if you go out into the cold," said Dr. Rachel C. Vreeman, co-author of "Don't Swallow Your Gum! Myths, Half-Truths, and Outright Lies About Your Body and Health." It's your body's way of combating the stress of freezing temps.
Plus, according to the National Institute of Allergy and Infectious Diseases, cold viruses grow best at about 91 degrees; if you're outside in the cold, your nostrils are surely colder than that.
Health.com: 5 most common myths about the common cold
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Photos: 10 winter health myths busted
Myth: You shouldn't exercise in the cold.
Get ready to crawl out from under your comforter and run into the great (and yes, cold) outdoors. According to research published in Medicine & Science in Sports and Exercise, in cold temperatures, race times are actually faster, and quicker paces burn more calories in less time. Plus, that harder, faster workout can spike your endorphin levels -- which, according to a review in Environmental Science and Technology, are already increased just by you being outside.
Ready to get started? Follow this guide to running in the cold.
Get ready to crawl out from under your comforter and run into the great (and yes, cold) outdoors. According to research published in Medicine & Science in Sports and Exercise, in cold temperatures, race times are actually faster, and quicker paces burn more calories in less time. Plus, that harder, faster workout can spike your endorphin levels -- which, according to a review in Environmental Science and Technology, are already increased just by you being outside.
Ready to get started? Follow this guide to running in the cold.
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Photos: 10 winter health myths busted
Myth: Allergies go away in the winter.
Allergies might be the real source behind your stuffy nose and scratchy throat this season. According to the Asthma and Allergy Foundation of America, one in five people suffers from indoor/outdoor allergies, and the indoor variety can actually be worse in the winter. Pets don't spend as much time outdoors, shut windows seal in poor air quality, and many molds even thrive in the winter, Vreeman says.
If your symptoms last longer than 10 days or ease up after taking an antihistamine, it might be time to visit an allergist.
Health.com: 15 hypoallergenic dogs and cats
Allergies might be the real source behind your stuffy nose and scratchy throat this season. According to the Asthma and Allergy Foundation of America, one in five people suffers from indoor/outdoor allergies, and the indoor variety can actually be worse in the winter. Pets don't spend as much time outdoors, shut windows seal in poor air quality, and many molds even thrive in the winter, Vreeman says.
If your symptoms last longer than 10 days or ease up after taking an antihistamine, it might be time to visit an allergist.
Health.com: 15 hypoallergenic dogs and cats
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Photos: 10 winter health myths busted
Myth: You don't need sunscreen in the winter.
Forget bathing suits. Department stores should stock sunscreen with the toboggan hats. "Because the Earth's surface is closer to the sun during the winter months, we are actually exposed to more harmful rays without even realizing it," said Dr. Robert Guida, a board-certified plastic surgeon in New York.
What's more, snow and ice can both reflect up to 80% of harmful UV rays so that they can hit the skin twice, according to the Skin Cancer Foundation. So even in winter, keep in mind these five ways to protect against skin cancer.
Forget bathing suits. Department stores should stock sunscreen with the toboggan hats. "Because the Earth's surface is closer to the sun during the winter months, we are actually exposed to more harmful rays without even realizing it," said Dr. Robert Guida, a board-certified plastic surgeon in New York.
What's more, snow and ice can both reflect up to 80% of harmful UV rays so that they can hit the skin twice, according to the Skin Cancer Foundation. So even in winter, keep in mind these five ways to protect against skin cancer.
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Photos: 10 winter health myths busted
Myth: You lose most of your body heat through your head.
Contrary to the findings from one 1950s Army study, most of your body heat doesn't escape through your noggin, according to Vreeman. "In the now-infamous study, volunteers visited the Arctic with their heads exposed. However, the rest of them was outfitted in gear designed to protect against the cold, so it's logical that they lost most of their body heat from their heads," she said.
If you go outside without gloves, you'll lose a disproportionate amount of heat through your hands.
Health.com: Winter skin annoyances, solved
Contrary to the findings from one 1950s Army study, most of your body heat doesn't escape through your noggin, according to Vreeman. "In the now-infamous study, volunteers visited the Arctic with their heads exposed. However, the rest of them was outfitted in gear designed to protect against the cold, so it's logical that they lost most of their body heat from their heads," she said.
If you go outside without gloves, you'll lose a disproportionate amount of heat through your hands.
Health.com: Winter skin annoyances, solved
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Photos: 10 winter health myths busted
Myth: Lack of sunlight causes winter depression.
Although dark days certainly don't help, there are many other factors besides seasonal affective disorder that can contribute to winter depression -- especially around the holidays.
Busy schedules, family stress and worries about holiday spending are more likely to trigger the blues than true SAD, which affects just 5% of Americans. Learn more about surprising causes of winter depression.
Although dark days certainly don't help, there are many other factors besides seasonal affective disorder that can contribute to winter depression -- especially around the holidays.
Busy schedules, family stress and worries about holiday spending are more likely to trigger the blues than true SAD, which affects just 5% of Americans. Learn more about surprising causes of winter depression.
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Photos: 10 winter health myths busted
Myth: Women gain 10 pounds over the winter.
Between comfort foods, dreary days and cozy blankets, it's not hard to imagine why women put on winter weight. But it turns out that the average woman gains only one or two pounds over the winter.
Still, one Nutrition Reviews study shows that weight gain during the six-week holiday season accounts for 51% of annual gain. And, according to research published in the New England Journal of Medicine, most women don't shed that extra layer of insulation come springtime, so over the years, the weight can really add up.
Health.com: 16 ways to lose weight fast
Between comfort foods, dreary days and cozy blankets, it's not hard to imagine why women put on winter weight. But it turns out that the average woman gains only one or two pounds over the winter.
Still, one Nutrition Reviews study shows that weight gain during the six-week holiday season accounts for 51% of annual gain. And, according to research published in the New England Journal of Medicine, most women don't shed that extra layer of insulation come springtime, so over the years, the weight can really add up.
Health.com: 16 ways to lose weight fast
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Photos: 10 winter health myths busted
Myth: Vitamin C prevents colds.
OK, this might be more of a half-myth. Meeting your 75-milligram recommended daily allowance of vitamin C is important in maintaining a healthy immune system to prevent and even fight off colds, according to one 2013 study from the University of Helsinki. Other studies have shown that taking a large dose of vitamin C at the first sign of sniffles may help shorten the length and reduce the severity of a cold.
Health.com: 12 foods with more Vitamin C than oranges
OK, this might be more of a half-myth. Meeting your 75-milligram recommended daily allowance of vitamin C is important in maintaining a healthy immune system to prevent and even fight off colds, according to one 2013 study from the University of Helsinki. Other studies have shown that taking a large dose of vitamin C at the first sign of sniffles may help shorten the length and reduce the severity of a cold.
Health.com: 12 foods with more Vitamin C than oranges
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Photos: 10 winter health myths busted
Myth: Cold temps cause hair loss.
Chilly weather might actually help you hold onto your hair. In one University Hospital of Zurich study, researchers followed 823 women for six years and found that they lost the most hair in the summer and the least in the winter.
It might be evolutionary; just think how thick your dog's fur gets in the winter. Still, dry scalps grow unhealthy, brittle and breakable hair, so if your head gets itchy on cold, dry days, you might need to invest in a scalp-protecting shampoo for the season, Vreeman says.
Health.com: 21 reasons why you're losing your hair
Chilly weather might actually help you hold onto your hair. In one University Hospital of Zurich study, researchers followed 823 women for six years and found that they lost the most hair in the summer and the least in the winter.
It might be evolutionary; just think how thick your dog's fur gets in the winter. Still, dry scalps grow unhealthy, brittle and breakable hair, so if your head gets itchy on cold, dry days, you might need to invest in a scalp-protecting shampoo for the season, Vreeman says.
Health.com: 21 reasons why you're losing your hair
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Photos: 10 winter health myths busted
Myth: Drinking alcohol warms you up.
Alcohol makes you feel toasty on the inside, but that's because it causes your blood to rush toward your rosy-red skin and away from your internal organs. That means your core body temperature actually drops post-sip, Vreeman says. What's more, alcohol impairs your body's ability to shiver and create extra heat.
Health.com: 7 ways to keep alcohol from ruining your diet
This article originally appeared on Health.com.
Alcohol makes you feel toasty on the inside, but that's because it causes your blood to rush toward your rosy-red skin and away from your internal organs. That means your core body temperature actually drops post-sip, Vreeman says. What's more, alcohol impairs your body's ability to shiver and create extra heat.
Health.com: 7 ways to keep alcohol from ruining your diet
This article originally appeared on Health.com.
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Although this year's vaccine is matching the most common strains so far, there have been so few cases of flu to date it is hard to say which virus will dominate this season, said Michael L. Jackson, an associate scientific investigator at Group Health Research Institute in Seattle.
If doctors could pick which strain they want to avoid, it would be H3N2. "H3N2 viruses tend to mutate faster than the other influenza virus types [and] years where H3N2 dominate tend to have more cases of hospitalizations," said Jackson, whose institute is part of the U.S. Flu Vaccine Effectiveness Network, a CDC-funded network that measures how well the vaccine is preventing flu cases every year.
New research suggests there could be another wrinkle in identifying which flu viruses are in circulation. Researchers looked at flu spread among 84 people in Hong Kong during the 2009 flu season. They found that, although H1N1 and H3N2 were predominant, individuals were also getting infected at the same time with other, less common viral strains.
"We tend to only detect the dominant strain in flu surveillance and design the vaccine based on that," said Elodie Ghedin, a biology professor at New York University, who led the study, which was published on Monday in the journal Nature Genetics. The study suggests these minor strains can persist in the population, and may even become predominant.
You should still get a flu shot
Even in the best-case scenario, when the commonly circulating strains match those in the vaccine, the vaccine usually only protects 50% or 60% of those immunized from getting the flu, Jackson said. The elderly and children are at highest risk of not being protected from the flu shot.
Although there are probably many still-unknown factors that determine why some people are protected and others aren't, it might be that the elderly population's immune systems do not perform as well as those of younger, healthier adults, Jackson said. Because of this, the CDC recommends that people 65 and older receive a high-dose flu shot.
Among children, other scenarios are probably at play; their immune systems are not mature enough to develop a proper immune response to flu vaccine, Bresee said. In addition, they have probably not been exposed to the flu virus, either through natural infection or immunization, and thus their immune systems have not been primed to recognize the virus. For this reason, children between 6 months and 8 years of age should receive two doses the first time they get the flu shot.
"Despite the fact that the vaccine doesn't work every time, it is still the best way to protect yourself against flu bar none," Bresee said. And it is worth getting a simple vaccine to protect against a disease that is far more dangerous than the common cold, and can lead to death and hospitalization even in healthy people, he added. (There are several groups of people who should not get a flu shot, such as those with allergies to ingredients in the vaccine.)
You can also protect yourself and others from the flu by doing "the things that your mom taught you -- wash your hands and stay home if you are sick," Bresee said. He also recommends that people who think they have the flu talk with their doctor about taking antiviral medications such as Tamiflu, especially if they are elderly or have conditions such as lung or heart disease that put them at higher risk of complications from the flu.
