How often should you get a flu shot? - Melvin Sanicas

Summary

Every year, a new flu vaccine is needed due to the influenza virus's high mutation rate and over 100 subtypes. Vaccines work by introducing antigens for the immune system to recognize, but the flu's RNA structure allows for rapid genetic changes, making it difficult for the immune system to keep up. Despite challenges, vaccines often provide protection even against mutated strains, reducing illness severity and supporting herd immunity.

Takeaways

• 🌐 Flu vaccines are developed annually because the virus mutates rapidly and has over 100 subtypes.
• 🛡 Vaccines for diseases like mumps provide lifelong immunity, unlike the flu vaccine which needs updating yearly.
• 🔬 The flu virus's RNA nature allows for faster mutation rates compared to DNA viruses.
• 🧬 Mutations in the flu virus can lead to new variants that may evade immunity provided by previous vaccines.
• 🏭 The flu virus hijacks host cells to replicate, leading to the production and spread of new viral particles.
• 💉 Vaccines work by introducing antigens to stimulate antibody production, which helps the immune system recognize and fight the virus.
• 🌀 The flu vaccine must be updated as new strains emerge and existing strains mutate.
• 🌍 The World Health Organization convenes experts twice a year to decide which strains to include in the upcoming vaccine.
• 💪 Even if the vaccine doesn't prevent infection, it can reduce the severity and duration of illness.
• 🤝 Vaccination contributes to herd immunity, protecting those who cannot receive the vaccine.
• 🧪 The flu shot cannot give you the flu; it contains an inactivated virus, and side effects are a normal immune response.

Q & A

Why is it necessary to design a new flu vaccine each year?

A new flu vaccine is needed annually because the influenza virus has over 100 subtypes that change from season to season, and it mutates more quickly than many other viruses due to its RNA nature.

How does the flu virus replicate within a host?

The flu virus replicates by entering a host cell, expelling its genetic material into the nucleus, where the host's cellular machinery starts replicating viral genes instead of the host's own, creating more copies of the virus.

What is the difference between DNA and RNA in terms of virus mutation?

DNA has a built-in proofreader that recognizes and corrects mistakes during replication, whereas RNA lacks this mechanism, allowing for faster mutation and the creation of new virus variants.

How does the flu vaccine work?

The flu vaccine contains antigens similar to those found on the virus surface. The body recognizes these as foreign and produces antibodies tailored to match the antigens, helping the immune system to quickly identify and fight off the virus if encountered.

Why is it challenging to create a vaccine for a virus that mutates rapidly?

Rapid mutations can alter the virus's surface compounds enough that previously developed antibodies may not recognize them, reducing the vaccine's effectiveness.

What is herd immunity and how does the flu vaccine contribute to it?

Herd immunity occurs when a significant portion of a community is immune to an infection, providing indirect protection to those who are not immune. The flu vaccine contributes by preventing carriers from spreading the virus, even if they themselves do not get sick.

Can the flu shot give you the flu?

No, the flu shot cannot give you the flu. It contains an inactivated virus that is not capable of causing illness, though it may cause temporary side effects like tiredness and aches as the immune system responds.

What is the role of the World Health Organization in the development of the flu vaccine?

The World Health Organization gathers experts twice a year to analyze circulating strains and their mutations, determining which strains to include in the upcoming season's vaccine.

How many strains are typically included in the quadrivalent flu vaccine?

The quadrivalent flu vaccine includes four strains of the influenza virus, chosen based on expert analysis by the World Health Organization.

What is the purpose of a universal flu vaccine?

A universal flu vaccine aims to protect against any strain of the flu virus, including mutated ones, eliminating the need for annual vaccinations.

Are there any alternatives to the flu shot?

Yes, some parts of the world use an inhaled vaccine that contains a weakened live virus, which is safe for the vast majority of people, except those with compromised immune systems.

Outlines

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💉 The Annual Challenge of Flu Vaccination

Researchers worldwide collect flu samples to design vaccines for the upcoming season. Unlike other vaccines that provide lifelong immunity, the flu vaccine must be updated annually due to the virus's ability to mutate rapidly and the existence of over 100 subtypes. The flu virus's genetic material is RNA, which mutates faster than DNA due to the lack of a proofreading mechanism during replication. Vaccines work by introducing antigens to stimulate antibody production, but the flu's mutations can alter these antigens, potentially allowing the virus to evade the immune response. The World Health Organization meets twice a year to decide which strains to include in the vaccine, aiming to predict which will be most prevalent. Despite the challenges, vaccines often provide some protection even against mutated strains, and contribute to herd immunity by preventing transmission.

Keywords

💡Vaccine

A vaccine is a biological preparation that provides active acquired immunity to a particular disease. In the context of the video, the flu vaccine is designed to protect against the influenza virus. The video explains that unlike some other vaccines that offer lifelong immunity, the flu vaccine must be updated annually due to the virus's high mutation rate.

💡Influenza virus

The influenza virus, commonly known as the flu, is a contagious respiratory illness caused by the influenza virus. The video highlights that there are over 100 subtypes of this virus, which can change seasonally, making it a moving target for vaccine development.

💡Antigens

Antigens are substances that, when introduced into the body, stimulate the production of an immune response. In the video, antigens are components of the flu vaccine that resemble parts of the virus. They are used to train the immune system to recognize and fight the actual virus.

💡RNA

RNA, or ribonucleic acid, is a molecule similar to DNA that plays a crucial role in protein synthesis and is the genetic material for some viruses, including the flu. The video explains that RNA viruses, unlike DNA viruses, lack a proofreading mechanism, leading to higher mutation rates, which complicates vaccine development.

💡Mutation

Mutation refers to changes in the genetic sequence of an organism. In the context of the video, the flu virus's rapid mutation is a significant challenge for vaccine developers because it means the virus can change its antigens, potentially rendering existing vaccines less effective.

💡Viral production factories

This term from the video describes how the flu virus hijacks a host cell to reproduce. The virus uses the cell's machinery to make copies of itself, eventually causing the cell to burst and release new viral particles. This process is central to how the flu spreads and why it's so difficult to combat with a vaccine.

💡Herd immunity

Herd immunity occurs when a large percentage of a population becomes immune to an infection, either through vaccination or previous infections, thereby providing a measure of protection for individuals who are not immune. The video mentions that vaccination not only protects the individual but also contributes to herd immunity, which can protect those who cannot be vaccinated.

💡Quadrivalent vaccine

A quadrivalent vaccine is a type of vaccine that protects against four different strains of a virus. The video explains that the World Health Organization selects four strains to include in the seasonal flu vaccine, aiming to cover the most prevalent and potentially dangerous strains.

💡World Health Organization (WHO)

The World Health Organization is a specialized agency of the United Nations responsible for international public health. In the video, WHO is highlighted for its role in coordinating global efforts to monitor flu strains and decide which strains should be targeted by the seasonal flu vaccine.

💡Universal flu vaccine

A universal flu vaccine is a hypothetical vaccine that would provide protection against all strains of the influenza virus, including those that have mutated. The video mentions that scientists are working towards developing such a vaccine, which would be a significant advancement in flu prevention.

💡Inactivated virus

An inactivated virus is a virus that has been treated to destroy its ability to cause disease but retains its antigenic properties, allowing it to stimulate an immune response. The video clarifies that the flu shot contains an inactivated virus and cannot cause the flu, addressing a common misconception.

Highlights

Researchers collect flu samples year-round for vaccine design.

A new flu vaccine is needed annually due to the virus's variability.

There are over 100 subtypes of the influenza virus.

The flu virus mutates more rapidly than many other viruses.

The flu spreads by turning host cells into viral production factories.

Flu's genetic material is RNA, which mutates faster than DNA.

RNA synthesis lacks a proofreading mechanism, allowing mutations to persist.

Vaccines rely on the recognition of viral antigens.

The immune system produces antibodies tailored to match vaccine antigens.

Vaccination prepares the immune system to quickly respond to the virus.

Antigens differ for each flu strain, complicating vaccine effectiveness.

Genetic mutations can alter the virus enough to evade antibodies.

Two different flu strains can combine to create a new hybrid virus.

Vaccinating for the flu is likened to hitting a moving, transforming target.

The World Health Organization meets twice a year to decide which strains to include in the vaccine.

Scientists' predictions for flu strains have been almost always correct.

Even with mutations, the vaccine often provides some protection.

Vaccination helps protect those who cannot receive the vaccine through herd immunity.

The flu shot cannot give you the flu as it contains an inactivated virus.

An inhaled vaccine is available in some parts of the world.

Scientists are working on a universal flu vaccine.

Transcripts

All year long, researchers at hundreds of hospitals around the world

collect samples from flu patients

and send them to top virology experts with one goal:

to design the vaccine for the next flu season.

But why do we need a new one every year?

Vaccines for diseases like mumps and rubella offer a lifetime of protection

with two shots early in life.

What's so special about the flu?

Two factors make the flu a tough target.

First, there are more than 100 subtypes of the influenza virus,

and the ones in circulation change from season to season.

And second, the flu's genetic code allows it to mutate more quickly

than many other viruses.

The flu spreads by turning a host's own cells into viral production factories.

When the virus is engulfed by a host cell, it expels its genetic material,

which makes its way to the nucleus.

There, cellular machinery that normally copies the host's genes

starts replicating viral genes instead,

creating more and more copies of the virus.

New viruses are repackaged and crammed into the cell until it bursts,

sending freshly minted influenza viruses out to infect additional cells.

Most viruses follow this script.

The trick with the flu is that its genetic material isn't DNA

but a similar compound called RNA.

And RNA viruses can mutate much faster.

When cells synthesize DNA,

a built-in proofreader recognizes and corrects mistakes,

but the RNA synthesis mechanism doesn't have this fail-safe.

If errors creep in, they stick around creating new variants of the virus.

Why is this a problem?

Because vaccines depend on recognition.

The flu vaccine includes some of the same substances, called antigens,

found on the surface of the virus itself.

The body identifies those fragments as foreign

and responds by producing compounds called antibodies,

tailor-made to match the antigens.

When a vaccinated person encounters the actual virus,

the preprogrammed antibodies help the immune system identify the threat

and mobilize quickly to prevent an infection.

Those antigens are different for every strain of influenza.

If vaccination has prepared the immune system for one strain,

a different one may still be able to sneak by.

Even within the same strain of flu,

those rapid genetic mutations can change the surface compounds enough

that the antibodies may not recognize them.

To make things even more complicated,

sometimes two different strains combine to create an entirely new hybrid virus.

All of this makes vaccinating for the flu

like trying to hit a moving transforming target.

That's why scientists are constantly collecting data

about which strains are circulating

and checking to see how much those strains have mutated

from previous years' versions.

Twice annually, the World Health Organization pulls together experts

to analyze all that data,

holding one meeting for each hemisphere.

The scientists determine which strains to include in that season's vaccine,

picking four for the quadrivalent vaccine in use today.

In spite of the flu's evasive maneuvers,

in recent years, the group's predictions have been almost always correct.

Even when flu strains mutate further, the vaccine is often close enough

that a vaccinated person who catches the flu anyway

will have a milder and shorter illness than they would otherwise.

Vaccination also helps protect other people in the community

who may not be medically eligible for the shot

by preventing those around them from carrying the virus.

This is called herd immunity.

The flu shot can't give you the flu.

It contains an inactivated virus that isn't capable of making you sick.

You might feel tired and achy after getting it,

but that's not an infection.

It's your normal immune response to the vaccine.

Some parts of the world use, instead of a shot, an inhaled vaccine

that contains a weakened live virus.

This is also safe for the vast majority of people.

Only those with impaired immune systems would be at risk,

but they're typically not given live vaccines.

Meanwhile, scientists are working to develop a universal flu vaccine

that would protect against any strain, even mutated ones.

But until then, the hunt for next year's vaccine is on.