It had been long held that this was most probably due to school children returning to schools and people being in closer proximity indoors in winter where they could pass all their germs around more easily. One of the most commonly cited studies used as a basis for this hypothesis was the "Seattle Virus Watch", done by John Fox, Carrie Hall, and friends. Another hypothesized explanation had been that our Vitamin D production is lower in winter due to less exposure of our skin to sunlight, and since Vitamin D improves the immune system's ability to fight off infections, our defenses were made weaker in winter with Vitamin D deficiency. Another commonly held belief was that in drier air our mucous tissues dry out and can crack making the viruses more easily introduced to the body. Some combination of all these factors may be at play.
However, the most recent studies have all seemed to point more to the different absolute humidity levels in winter compared to those in summer in the northern hemisphere. In February 2010 results were published of a study that used mathematical modeling of 31 years of data about the absolute humidity levels. That study, which was supported by the US National Institutes of Health (NIH) and in association with Oregon State University, reproduced the same seasonal variations in incidence of flu as has been observed for centuries or longer (although over that time frame the reason for the variations had not been known).
Most scientists now agree that there is a correlation between the absolute humidity levels and the spread of the flu, which several more recent studies have suggested. The studies indicate that variation in the absolute humidity is a major cause of seasonal cycles of influenza.
This also helps explain why in some locations in the world the flu season is during the warmer times and not in fall and winter. It is more the effect of absolute humidity and not the temperature itself that makes that difference. In areas with the flu season in warmer months, the absolute humidity is lower then, making the dry conditions that influenza viruses prefer despite warm temperatures. In the US, the absolute humidity levels are lowest during the peak of the flu season in January and February, the colder season.
Flu viruses like it dry: they spread more easily when it is drier and also survive longer outside a host in those conditions. There is some speculation that significantly increasing the humidity in your home in winter could help prevent flu infections.
Absolute humidity is a measure of the total amount of water in the air (without factoring in the temperature). Relative humidity, which is the measurement that we usually get in weather reports, is based on a combination of temperature and moisture. In some areas of the US in summer there can be four times more water vapor in the air than on a winter day. It is believed that this impacts the seasonal variations since flu does not like more water vapor. The saturation level of water vapor in the air varies with the temperature. Warm air can "hold" the same amount of water vapor at 30% relative humidity as cold air has at 60% relative humidity.
Therefore, while it may not be totally proven as the sole cause of flu seasons, it is very likely that the variation in absolute humidity is a major impacting factor for why we have seasonal flu infections.
The exact duration of the flu season varies by hemisphere and environmental factors. In the northern hemisphere, the flu season occurs in the winter.
what date is the officially end to the flu season 2014
It is now. Since the 2010-2011 flu season, the seasonal flu vaccine has contained the swine flu vaccine in addition to two other types of flu vaccines that were selected for each specific flu season. There is no longer a need to get two flu vaccinations like was required in the 2009-2010 flu season during the pandemic.
There are many websites that offer information about the flu season. The CDC, TexasFlu, flu.gov, and immunisation websites all offer helpful information about the flu season.
Once flu season is over....which I think is may or June...but when flu season comes back around november, so does the swine flu.
They are available now. In fact, in the 2010-2011 flu season in the Northern Hemisphere, the regular seasonal flu vaccination includes the vaccine for H1N1/09 (swine flu). If you already had the vaccine in the 2009-2010 season, it will not harm you and might help you to get it again along with the vaccines for the other flu viruses expected in this flu season.
Flu Season - 1999 was released on: USA: 31 October 1999
The vaccine was first distributed just at the beginning of the 2009 flu season in the Northern Hemisphere. It is included in the regular seasonal flu vaccination again in the 2011-2012 flu season.
It probably won't suddenly stop spreading, but it dies down after each flu season. It comes back during the next flu season though.
Last flu season, 2009-2010, you needed two shots. But this year the seasonal flu shot also protects against swine flu, so, in the US, you only need one flu shot for the 2010-2011 flu season.
The swine flu is no longer a pandemic. Outbreaks are still occurring in some places of the world. It really didn't involve only the flu "season" but also was spreading in spring and summer, not typically times for the flu. At present (spring 2011), the northern hemisphere is in the flu season which is usually defined as the period from October until April in the northern areas. One of the types of flu that was anticipated and that has been active during this flu season is the H1N1/09 Swine Flu. That is why this year's flu season vaccine incorporated the swine flu vaccine as one of the three in the seasonal trivalent flu vaccination for 2010-2011's flu season. Ohio is included in this flu season of October to April, so since it is currently mid March 2011, the flu season will be over in Ohio in a few weeks. However, just because the season is over, does not mean you can not still get the flu, especially since we know that the swine flu began in spring 2009. Most people do not get a flu vaccination after the end of March, however, since the time to become immune from the response to the vaccine is longer than the season usually lasts from that point. There is still some risk, so some doctors continue to give the vaccine through the end of March. It is important to get the seasonal flu vaccination each year in the early fall in the Northern Hemisphere to prevent the flu.
They usually are available a month or so before the start of the flu season. In the Northern Hemisphere and US that is around September since the beginning of the flu season is October.
Seasonal flu vaccines should be taken annually about a month prior to the flu season.
When the Influenza season starts or when the flu is at its highest potential
That will only be needed if a new mutation of the swine flu occurs that the current swine flu vaccine isn't able to prevent. In the 2009-2010 flu season in the US two shots were need, the regular seasonal flu shot and the H1N1/09 Swine flu shot. But in the current 2010-2011 flu season in the US, the seasonal flu vaccination contains the vaccine for swine flu in addition to the other varieties of flu that are expected to be circulating. So only one shot is needed this year for protection in the flu season.
Get your swine flu (H1N1/09) vaccination prior to the fall and winter flu season in your location. That is right now (October - March) in the Northern Hemisphere. The vaccine for swine flu prevention is included in the regular seasonal flu vaccines in the 2010-2011 flu season, so unlike 2009, there is only a single vaccination required to cover all types of flu that are anticipated to reach us during this season.
They don't shoot you, and it isn't a 'shot' of a drink, it's a needle in the arm. In the 2009-2010 flu season there was a mist as well as a shot for the vaccination for swine flu. In the 2010-2011 flu season the vaccine for swine flu protection is included in the one vaccination for the seasonal flu.
Yes, and, since the seasonal flu vaccination in the US contains the vaccine for three different types of flu, you should get that to be sure you are covered for the main types expected to be circulating in the environment during each flu season.In the Northern Hemisphere (including the US), the flu vaccine is recommended to be given through the end of March since the flu season is still active until April. After that, it is usually okay to wait until the beginning of the next flu season for the vaccination in the fall around September or October.
If you do not take a flu shot there are fair chances that you will catch the flu in the next flu season. Medical professionals recommend annual vaccinations against the flu.
the only way to know if its swine flu is if its not in the regular flu season like summer
As of the 2011-2012 flu season, it is still circulating in isolated outbreaks. In the Northern Hemisphere there are scattered outbreaks seen. It is expected to be one of the three most common types of flu during this flu season and, therefore, the seasonal flu vaccination protects against it again this year.
During fall and winter.
In 2009, it was October 4-10. Flu season always begins in the 40th week. In 2009, flu season began on October 4.
Stores like Walgreens and CVS
The vaccine for the 2009 pandemic swine flu was released just around the beginning of the flu season in 2009-2010.