What is Influenza?
Influenza, also known as “flu”, is a transmissible disease precipitated by viruses that taint the respiratory tract basically nose, throat, and lungs. Influenza causes severe illness and lethal health impediment in the victim.
Influenza virus is an antigenically and genetically diverse group of viruses of the family Orthomyxoviridae that contains a negative-sense, single-stranded, segmented RNA genome according to the National Institute of Health.
General perception of Influenza.
Most people don’t see Influenza as a serious illness – the general symptoms of headaches, runny nose, cough and muscle aches can make people confuse it with a heavy cold. Yet seasonal influenza kills almost 650 000 people per year according to world health Organization. That is why influenza vaccinations are so important, especially to protect young children, older people, pregnant women, or people who have vulnerable immune systems.
Public opinion of ‘the flu’ is that it is seasonal, majorly because it comes around twice a year (During the Northern and Southern hemisphere’s winter) in benign zones of the world, and flows year-round in the sultry and subtropics. The influenza virus is constantly metamorphosing i.e. putting on ever-changing disguises – to evade our immune systems.
The flu pandemic in Retrospect
The first record of the flu was dated back to the 1918 pandemic, it struck with an intensity and speed which was almost unimaginable – making impure one third of the Earth’s population third (Then approximated to about 500 million people). By the time the pandemic subsided after two years, more than 50 million people are estimated to have died. Globally, the death toll eclipsed death recorded during the First World War, which was around 17 million.
Latest World update on Influenza
FluNet is a global web-based tool for influenza virological surveillance first launched in 1997. The virological data entered into FluNet, e.g. number of influenza viruses detected by subtype, are critical for tracking the movement of viruses globally and interpreting the epidemiological data.
National Influenza Centers (NICs) and other national influenza laboratories from 112 countries, areas or territories reported data to FluNet for the time period from 28 October 2019 to 10 November 2019 (data as of 2019-11-22 05:24:24 UTC). The WHO GISRS laboratories tested more than 85 126 specimens during that time period. A total of 6187 were positive for influenza viruses, of which 4608 (74.5%) were typed as influenza A and 1579 (25.5%) as influenza B. Of the sub-typed influenza, a virus, 1473 (47%) were influenza A(H1N1) pdm09 and 1664 (53%) were influenza A(H3N2). Of the characterized B viruses, 43 (6.2%) belonged to the B-Yamagata lineage and 650 (93.8%) to the B-Victoria lineage.
The WHO Consultation and Information Meeting on the Composition of Influenza Virus Vaccines for Use in the 2020 Southern Hemisphere Influenza Season was held on 23-26 September 2019 in Geneva, Switzerland. It was recommended that trivalent vaccines contain the following: A/Brisbane/02/2018 (H1N1) pdm09-like virus; an A/South Australia/34/2019 (H3N2)-like virus; and a B/Washington/02/2019-like (B/Victoria lineage) virus. It was also recommended that quadrivalent vaccines containing two influenza B viruses contain the above three viruses and a B/Phuket/3073/2013-like (B/Yamagata lineage) virus.
Types of Influenza Viruses.
According to the Centre for disease control and prevention, there are four types of influenza viruses: A, B, C and D. Human influenza A and B viruses cause seasonal epidemics of disease (known as the flu season).
Influenza A viruses are the only influenza viruses known to cause flu pandemics, i.e., global epidemics of flu disease. A pandemic can occur when a new and very different influenza A virus emerges that both infects people and has the ability to spread efficiently between people.
Influenza type C infections generally cause mild illness and are not thought to cause human flu epidemics. Influenza D viruses primarily affect cattle and are not known to infect or cause illness in people.
Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus: hemagglutinin (H) and neuraminidase (N). There are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes (H1 through H18 and N1 through N11, respectively). While there are potentially 198 different influenzas A subtype combination, only 131 subtypes have been detected in nature.
Current subtypes of influenza A virus that routinely circulate in people include: A(H1N1) and A(H3N2). Influenza A subtypes can be further broken down into different genetic “clades” and “sub-clades.” See the “Influenza Viruses” graphic below for a visual depiction of these classifications.
Most vulnerable victims.
Viruses are oblivious to age, international borders, social and economic status. Influenza is cyclically deadly in very young or elderly people; statistically the 1918 influenza pandemic was unusually fatal among men aged 20 to 40 years. This stratum represents the most active force of the economy hence disrupting the economy and social echelon like school, work and recreational get together.
How the flu works in victim’s body.
According to a researcher on a journalistic flair platform, he describes the Influenza virus work on the victim as gradual in stages. It is inhaled or transmitted, most times along the fingers, then the mucous membranes of the nose, eyes and mouth, next It moves to the respiratory tract and affects the epithelial cells in the lung airways through specific molecules on the cell surface. It then hijacks the protein producing cells and starts creating its own viral proteins and particles. This process replicates to invade adjacent cells and gives rise to lung injury.
Role of Body Immunity during attack.
The symptoms of flu are caused and determined by the body immune response to the virus. The initial immune response involves cells of the victims’ innate immune system (macrophages and neutrophils). These immune cells express receptors that detect the presence of the virus which naturally triggers a warning by assembling the cytokines and chemokines at this point establishing the body has been affected. The cytokines adapt the other components of the immune system to appropriately fight the invading virus, while chemokines direct the components to the area of infection. The T lymphocytes cell (A white blood cell/Soldier cell) is deployed to work by the body system, because of its ability to recognize influenza viral proteins and particles proteins, which begin to escalate the lymph nodes around the lungs and throat, causing swell and pains in these nodes.
In a matter of days, these T cells migrate to the lungs and begin to kill the virus-infected cells. This process creates copiousness of lung damage like the bronchitis, capable of worsening existing lung disease and unease breathing. The perfect functioning of influenza-specific T cells is critical for efficient clearance of the virus from the lungs.
Thus, while you feel miserable when you have an influenza infection, you can rest assured that it is because your body is fighting hard to combat further spreading of the virus in your lungs and killing infected cells.
A look at the symptoms of Influenza
While the symptoms of Influenza may vary in individual at the onset which is the level of body immunity to resist the viral growth, it is generally observed that the following manifest basic symptoms of the flu and should trigger suspicion. It can take 1 to 4 days for symptoms to appear after exposure to the virus. The symptoms of influenza include fever (having temperature above 39°C), cough, and muscle aches. Other general symptoms include sore throat, runny nose, headache, chills, fatigue and loss of appetite. While some adults will also experience stomach ache, vomiting and diarrhea, but these symptoms are more common within children.
Most victims of flu recover fully between 7 and 10 days. However, some mostly the or with chronic health conditions can develop serious complications along the line. These could include pneumonia and aggravation of pre-existing medical conditions such as congestive heart failure, asthma, or diabetes.
Ways to avoid getting the flu.
- Get the flu vaccine every year – even if you do get the flu, your symptoms will be milder (A detailed articulation of the importance of vaccination is treated afterwards)
- Avoid being around people who are sick
- Try not to touch your eyes, nose or mouth – germs are most likely to enter your body this way
- Clean and disinfect surfaces if you are sharing a home with someone who is sick
- Wash your hands regularly.
Things to do if you have the flu.
- Cover your mouth and nose when coughing or sneezing.
- Wash your hands regularly
- Drink plenty of water and rest
- If you have a vulnerable immune system, you may need antivirals
- Don’t take antibiotics – they don’t work against cold or flu viruses.
Importance of Flu vaccination
According to latest Publications on Influenza Vaccine Benefits Flu vaccination prevents you from getting sick with flu.
From statistics flu vaccine prevents millions of illnesses and flu-related doctor’s visits each year. For example, between 2017 and 2018, flu vaccination prevented an estimated 6.2 million influenza illnesses, 3.2 million influenza-associated medical visits, 91,000 influenza-associated hospitalizations, and 5,700 influenza-associated deaths. Flu vaccination can reduce the risk of flu-associated hospitalization for children, working age adults, and older adults.
Flu vaccination is an important preventive tool for people with chronic health conditions.
Flu vaccination has been associated with lower rates of some cardiac events among people with heart disease, especially among those who had had a cardiac event in the past year.
Flu vaccination can reduce worsening and hospitalization for flu-related chronic lung disease, such as in persons with chronic obstructive pulmonary disease (COPD).
Flu vaccination also has been shown in separate studies to be associated with reduced hospitalizations among people with diabetes external icon and chronic lung disease. Flu vaccination helps protect women during and after pregnancy.
Vaccination reduces the risk of flu-associated acute respiratory infection in pregnant women by about one-half.
A 2018 study that included influenza seasons from 2010-2016 showed that getting a flu shot reduced a pregnant woman’s risk of being hospitalized with flu by an average of 40 percent.
A number of studies have shown that in addition to helping to protect pregnant women, a flu vaccine given during pregnancy helps protect the baby from flu for several months after birth, when he or she is not old enough to be vaccinated. Flu vaccine can be life-saving in children.
Getting vaccinated yourself may also protect people around you, including those who are more vulnerable to serious flu illness, like babies and young children, older people, and people with certain chronic health conditions.
Influenza can be prevented by annual vaccination. In Canada, the National Advisory Committee on Immunization (NACI) recommends that all Canadians older than six months get a flu shot.
The influenza vaccine is highly recommended for the following people due to a higher risk of hospitalization:
- Adults (including pregnant women) and children with chronic heart or lung disease.
- People of any age who are residents of nursing homes and other long-term care facilities.
- People over the age of 65 years.
- Children between 6 months and 5 years.
- People with health conditions such as diabetes, cancer, heart disease, lung disease, obesity, etc.
- Healthy pregnant women.
- Indigenous peoples.
The vaccine is also recommended for people who are capable of transmitting influenza to those at high risk. For example, health care workers, those providing essential community services, people (e.g., family, household members, caregivers) who have close contact with those listed as high risk, those who care for or are expecting a newborn baby during flu season, health care workers, child care workers, or those who live or work in situations that have close contact (e.g., crew on a ship).