Winter....

We do get sick in the winter and it is not because of the cold weather as my grandma used to say.
During the winter we are mostly huddled together in one room, under the blankets, we close the windows and keep warm with a nice fire in the fire place, or with the air condition blowing nice warm air into the rooms.
A breeding place for bacterias and viruses. If someone has a running nose we will all get it, because of the proximity with the bearer. Viruses and bacterias that are transferred through the air have no difficulties passing from one to the other, the same as those passed via touch and saliva.
Mind you,  the hot summer days are not so different since we are also then huddled in one room with the aircondioner going fulll blast escaping the heat outside, we might be huddled under a blanket or not... and again the perfect breeding place for viruses and bacterias is created around us.
So, the typical winter flu is becoming the "year-round-flu" bcause of lifestyle and modern inventions.
Fresh air -warm and cold- in summer and winter can help prevent infections also a healthy lifestyle (plenty of fresh veges, fruits and outdoor) and of course good mood and optimistic outlook in life.
Open the windows every day and sleep with an open window, also when you have the flu - or especially then -, go to the beach when you are coughing and breath in some good sea air, that is less polluted than the air we breath in the city. You have a stuffy nose? Go outside and exercise it frees the sinuses.
Last not least, clean all the pipes of the aircondition not only the net. This has to be done by a professional technician every year. The stuff that comes out of the vents together with heat or cold air, is dirt and pollutes the air in the house with allergens viruses and plenty of bacteria

Yes, it is that simple, and I haven't even reached for my supplements and homeopathic medicines yet, not to say nothing about calling the doctor!