Posted on : November 25, 2022 by Clinic One Team on Flu Vaccines
Influenza which is commonly called “flu” is the most prevalent disease around the globe.
It primarily causes infection of the respiratory system such as the nose, throat, and lungs, and can cause some serious complications, especially for younger children, along with older adults especially over 65 years and older.
Prevalence in Nepal and globally
Each year 5–15% of the population contracts influenza and among them 3–5 million cases are severe. About 2,90,000 to 6,50,000 deaths occur every year due to respiratory disease caused by flu every year.
There are almost 4 different common types of influenza viruses that preside over others in a typical flu season.
Flu seasons are synchronized lasting from January-February and July-August in Nepal.
Among them Influenza A/H3 strain constitutes almost (51%) of cases, influenza B constitutes almost (40.4%) of the cases, while influenza A (H1N1) pdm09 strain accounts for almost (8.6%) annually.
Geographical Impact of Nepal on Flu Strain
Generally speaking, research suggests that in the case of temperate climates, winters predominate the seasonal patterns of incidence of these flu viruses, while in tropical regions, disease burden is equally scattered throughout the year making the occurrence of outbreaks quite irregular.
And since, Nepal with its geographical diversity incorporates all the seasonal diversity including subtropical climate in the plains, warm temperate conditions in the hilly regions, and cool temperate conditions in the higher parts of the mountains making the modeling, and predicting the outbreak of flu strains and seasons, a tough job.
Nevertheless, there are 4 different types of seasonal influenza viruses that predominate globally, including Influenza viruses, type A, type B, type C, and type D, amongst which Influenza viruses type A, and B are most prevalent in Nepal.
Types of Strains
Influenza A Virus
Commonly circulating “A” type influenza viruses in humans include A(H1N1), and A(H3N2), globally. There has been differentiation according to the combination of surface proteins on the viruses such as hemagglutinin (HA), and neuraminidase (NA). Type A (H1N1) is also written and seen in the articles as A (H1N1) pdm09 since it caused a pandemic in 2009, and hence replaced the A(H1N1) strain, circulating previously to it.
Influenza B Virus
Currently found strains of type B viruses belong to either B/Yamagata or B/Victoria lineage. But it has not been further classified into any subclasses.
Influenza C Virus
This type of influenza virus is detected less often and also causes mild infection, hence it is not recognized as being of any impact on public health importance.
Influenza D Virus
These are known to occur and infect cattle and not humans thus making it less significant to study for human medical importance.
Yearly Changes in Flu Strains
Flu viruses are very susceptible to rapid changes in their strains attributed mainly to two biochemical phenomena called “shift and drift”.
In the phenomenon called antigenic drift, there are subtle changes in the genetic composition of flu strains altering the changes on their surface proteins of the viruses such as (HA) hemagglutinin, and (NA) neuraminidase, which brings about subtle changes in the strains every year which could accumulate over time to produce an entirely new strain in a long run.
While in contrast, the process of antigenic shift creates abrupt and big changes in viral genotype that brings about major changes in the surface proteins (HA), and (NA) that these viruses express on their surface.
These are characterized by the evolution of sudden new viral strains that can cross species borders amongst the host that they can infect, resulting in making animal flu viruses capable of infecting humans for which humans may not have any innate resistance.
This occurred in 2009 when flu viruses from “North American Swine” viruses started infecting birds and consequently humans making it a pandemic that created havoc all around the globe.
Influenza is commonly characterized by some of these symptoms including:
- Onset of fever
- Cough (usually dry)
- Muscle or joint pain
- Feeling unwell
- Sore throat
- Running nose
Usually, cough and fever can last for about a week or so, ranging from mild to severe, while people recover from it without requiring any medical attention.
But if you are in a high-risk zone (young ones and elderlies), symptoms can be serious, and sometimes fatal.
Impact of Development Index on Epidemic
Strangely speaking, cases of fatalities in developed countries have been associated with the elderly population of 65 years and older, while, in developing countries, it is seen amongst young children that are below 5 years.
There has been attributed generally to the infection of the lower respiratory tract that is prevalent in developing countries.
All age groups are susceptible to this disease but certain age groups are more at risk than others such as:
- Young children under the age of 5
- Elderly people over the age of 65
- People with previously identified chronic medical conditions
- Individuals with immune suppressive conditions (people suffering from HIV-AIDS, people undergoing chemotherapy)
- Pregnant women
Influenza is one of the most communicable diseases that can spread easily, especially in crowded areas. These areas include schools, shopping centers, and nursing homes or hospitals that have a high frequency of patient flow.
It spreads when an infected person coughs or sneezes, emitting viruses in the air droplets that are dispersed nearby for about 1 meter or more and consequently inhaled by uninfected people.
Thus, it is recommended for infected people to cover their mouth and nose with tissue paper or a towel while they cough or sneeze and not let these viruses spread through in the air.
Moreover, frequent washing of hands with soap and water and constant wearing of masks can be very vital preventive measures to mitigate the transmission of these viruses while they are in crowded areas.
While the application of a flu shot or flu vaccine is a very wise way to mitigate the adversities of any flu season, especially for those susceptible ones.
Call us at 9861966614 to get a Flu Vaccine in Nepal or Request an Appointment below.
Introduction of New Quadrivalent Flu Vaccine in Nepal
Quadrivalent flu vaccine incorporates protection for four different types of influenza strains, namely two strains of influenza type A and two strains of influenza type B in a single shot.
It is usually administered intravenously or taken as a suspension. Since it confers protection from both the most commonly prevalent influenza strains in humans, hence its use is incomparable to others.
Since not all healthcare providers might have this flu vaccine, you might need to inquire about the presence of the Quadrivalent flu vaccine with your healthcare professional and its availability to ensure a shot before any flu season for optimal protection.
Who needs the Flu Vaccine, Who does not and Why?
Everyone over the age of 6 months or older is recommended to get an annual flu vaccine every season, except for certain conditions. So if you are suffering from chronic diseases or other health problems doctor’s consultation is a must.
Moreover, there is no preference or recommendation for any one vaccine over another for people younger than 65 years.
This is to say, these people can get any variety of clinically approved vaccines available in the market, while there are few recommendations made by the CDC for people over the age of 65 years.
In other words, 3 flu vaccines are recommended for people aged 65 years or older as of the clinical review made by the CDC on the 2022-2023 flu season.
These are namely
- Fluzone High-Dose Quadrivalent Vaccine
- Flublok recombinant Quadrivalent Flu Vaccine
- Fluad Quadrivalent Adjuvanted Flu Vaccine
While, on the other hand, young children under the age of 6 years and those who have severe life-threatening allergies to any ingredient in the flu vaccine including gelatin, antibiotics, other any other ingredients should not receive any flu vaccine or talk to their physicians beforehand.
Still Have Queries about Flu Shot in Nepal? Send us a message Now.
References: Bimalesh Kumar Jha, et al (2020) Overview of seasonal influenza and recommended vaccine during the 2016/2017 season in Nepal, Published in “National Library on Medicine”. CDC (2021) Article on Influenza: How flu viruses can change: Drift and Shift CDC (2022) Influenza (Flu), Article on “Who should and who should not get a flu vaccine” CDC (2022) Influenza (Flu), Article on “Quadrivalent Influenza Vaccine” Mayo Clinic (2022) Article on “Flu shot, your best bet for avoiding influenza” World Health Organization (WHO) (2018) Influenza (Seasonal)
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