Flu season affects the United States annually, primarily starting in late fall, and ending in early spring after it has reached its peak.

Although most people who become infected with the flu or influenza can recover without much hassle, the flu can cause severe symptoms that ultimately can lead up to a premature death, especially for older adults, pregnant women, and young children. Deaths from influenza between 1976 and 2007 ranged from 3,300 to 49,000 annually, making timely vaccination a must.

Man with a flu
Image credit: iStock.

How flu vaccines are selected

The CDC commissioned an Influenza Work Group to analyze the rightful means of procedure for tackling each year’s influenza season. Because vaccines change each year, the public vaccination process must be carefully covered and implemented to protect the population from this potentially deadly disease.

The recommendations for vaccines are also made by the World Health Organization alongside the FDA, reviewing similar data and making a plan for the vaccines to be marketed within the U.S.

Influenza Vaccine
Influenza Virus vaccine. Image credit: Organic Lifestyle Magazine.

According to the CDC, new influenza viruses emerge due to mutations and recombination events, allowing them to become immune to common antigens that reduce the chance of infection. Being resistant toward one type of influenza virus does not guarantee immunity against other strains or subtypes.

One of the main objectives of the CDC for each flu season is to determine the timing of the onset, peak, and end of influenza activity. Besides age group differences, people that are at risk of suffering severe influenza illness are those with chronic cardiovascular and pulmonary disease. Also, during the 2009 pandemic, the CDC observed that there was a high prevalence of obesity among patients with severe illness associated with influenza strains.

A vaccine may be effective depending on many factors, among which the most important may be the age and immunocompetence of the patient. The composition of the vaccines is always determined months before the season begins. In some cases, circulating viruses might differ from the ones present in the vaccine, which is why influenza vaccines are not 100 percent reliable.

The CDC explains that the immunity provided by the vaccine lasts for at least six months for nonelderly people, although many cases display a longer period of protection.

Seasons, strains, and peaks

Currently, the CDC suggests that flu season has not reached its peak yet, which means that there is still half of a season to get vaccinated before it’s too late. The 2016-2017 flu season appears to be hitting harder the East and West coasts of the country, especially the Northwest, where CDC epidemiologists believe that the region has reached the peak of its flu season.

The most widespread strain is H3N2, which apparently has a much more intense group of symptoms for the young and the elderly, although this year being an H3 year has been discarded from being the most severe. The CDC recommends getting a flu shot as soon as possible, and if the patient still gets infected, it will be milder than if the patient had not gotten the vaccine.

An illustration representing H3N2 strain. Image credit: Outbreak News Today.

If vaccination is not an option, the CDC recommends taking Relenza, Tamiflu, or any drug containing oseltamivir, zanamivir, and peramivir, if the infection has not developed much with time.

“Because the peak month for influenza activity can range from December to March, getting vaccinated at this time still offers substantial public health benefits. While how well the vaccine works can vary, flu vaccine is the best way to protect against flu,” reads the report published by the CDC.

Currently, the Washington State Department of Health has reported 46 deaths due to influenza, where 38 of them were people 65 years old or older. Hospitalization rates in some counties appear to double and triple the rates of previous seasons.

What immunology dictates is that some disease could be inoculated in people to confer immunity. That is what Benjamin Jesty did with his family in the 19th century, as he inoculated them with cowpox, making them immune to smallpox. Additionally, becoming infected naturally with the disease confers immunity, and both of these discoveries allowed physicians to step into a new panorama of how diseases evolve to affect our bodies and how the immune system reacts.

In contrast to smallpox, the virus of influenza changes rapidly its hemagglutinin and its neuraminidase, which helps it bind to other cells and allow the virus to infect them. Vaccines usually target both of these molecules, helping the immune system recognize them as threats and “learning” about how to defend the organism against it. The main problem is that hemagglutinin and neuramidase change without too much trouble, allowing the virus sometimes to pass unnoticed in front of current vaccines.

In reality, researchers determine the types of flu that are perhaps going to be the most likely to infect large populations, and then they manufacture the vaccine to help people combat the illness, although it is not always useful as one would expect.

Source: CDC