Flu can last at least five days in healthy adults and a month or longer if your resistance is reduced by old age or other health problems. Eight out of ten asthma attacks in children are triggered by upper respiratory tract infections such as colds, sore throats and 'flu. The 'flu virus is transmitted from person to person in virus-laden droplets that are expelled during coughing and sneezing. Symptoms may include a fever, dry cough, sore throat, runny nose, chills, fatigue, headache, loss of appetite and muscle aches. Although the vaccination takes up to 14 days for antibody levels to rise sufficiently to provide protection, it will last for a year.
Studies suggest that it is very rare for the 'flu vaccination to trigger asthma symptoms.
Sometimes, because the injection is given in the autumn, people develop asthma symptoms due to a cough or cold they caught before the infection. The vaccine itself cannot cause 'flu because it contains no live virus. Cutting allergen levels in the home can help reduce your asthma symptoms. Wrapping up warm and taking steps to avoid catching colds and flu can also help people with asthma.