Influenza Prevention, Vaccination, and Treatment

Table of Contents

Influenza (flu) is a contagious respiratory infection that takes a toll on people across the world every year. Influenza viruses are responsible for causing the flu, which can be mild or moderate, and, in some instances, can even cause hospitalization or death in those at high risk, such as the elderly, small children, and those with chronic illnesses. Millions of cases occur during flu season, and public health is severely impacted, with a huge burden falling on the healthcare systems. It’s essential to prevent and treat influenza so it can be kept at a minimum while also reducing complications.

Historical Context: The 1968 Influenza Pandemic

The 1968 influenza pandemic, or H3N2, was a global outbreak that started in Hong Kong. The new H3N2 flu A virus hit in early 1968 and soon spread to Asia and beyond. By the year’s end, the virus was in the US and thriving on all continents. The pandemic claimed as many as one million lives around the world, of which about 100,000 in the U.S., most of them among the elderly.

The H3N2 virus had evolved from previous influenza A viruses through a mutation in hemagglutinin protein, creating a new strain against which people had little defense. With increased air travel, the virus swept around the world in a flash, proving just how quickly influenza infections can affect everyone. The pandemic also made the need for global health planning and public health response crucial. Our lessons from 1968 inform the way we now track flu strains, develop vaccines, and tailor responses to future flu outbreaks.

Influenza Vaccination: Why and Who Should Get Vaccinated

Every year, individuals and communities must be vaccinated against influenza. Vaccination boosts immunity and decreases the severity of illness in people who might get the flu. Some groups have a higher potential for severe flu complications, so it’s especially important for them to get vaccinated.

Flu Shots

Who Can Receive the Flu Shot

Most people are encouraged to get flu shots, though different vaccines are geared to different age ranges. Here’s a breakdown of who needs the flu shot and what they need to know.

Eligible Groups for the Flu Shot

The vast majority can get vaccinated against the flu without risk. For ages 6 months and older, routine inactivated flu vaccines are available. Some vaccines, however, are designed for older patients. The recombinant flu vaccine, for example, is for adults 18 years and over, while the adjuvanted and high-dose inactivated vaccines are for those 65 years or older, offering extra safeguards for the elderly.

Flu shots are also recommended for pregnant women and patients with chronic illnesses, as they reduce the chances of serious flu complications. Also, people with egg allergies can take any flu vaccine that works best for their age and condition, even if it’s egg-based.

Who Should Avoid the Flu Shot

Some groups should not get the flu vaccine at all. Flu shots cannot be given to babies younger than 6 months old. Further, anyone who has had a life-threatening allergic reaction to any component of the vaccine (e.g., gelatin or antibiotics) should not be given that exact flu vaccine again. If you have had a severe reaction to a flu shot, speak with your physician before getting a new one.

When to Consult a Healthcare Provider about a Flu Shot

Some diseases require an appointment with a physician prior to a flu shot. Tell a doctor if you are a Guillain-Barré syndrome (GBS) patient, as you may be recommended not to get vaccinated in some instances. The same goes if you’ve had a severe reaction to any flu vaccine; discuss it with your provider and work out the best route forward. Last, if you are not feeling well on the day of your shot, talk to a healthcare provider about your symptoms.

Importance of Immunity and Effectiveness of Flu Shots

Flu virus mutations occur every year, and flu vaccines are revised each year to be compatible with the latest strains. Flu vaccines don’t always work 100% of the time, but they’ve been shown to substantially decrease the risk of extreme illness, hospitalization, and complications. Vaccination also promotes population immunity, preventing the spread of the flu and safeguarding those who are not vaccinated (for example, infants younger than six months old).

Nasal Spray Flu Vaccine

Eligibility for the Nasal Spray Flu Vaccine

The nasal spray flu vaccine is recommended for people between 2 and 49 years old. It’s an alternative to the flu shot for many people of this age. However, some groups cannot use the nasal spray because of the potential for harm, including pregnant women and individuals with certain conditions.

Who Should Not Receive the Nasal Spray Vaccine

The following people should avoid the nasal spray flu vaccine:

Children under the age of 2 years.
Adults 50 years or older.
Patients with a previous history of serious or life-threatening allergic reactions to any component of the nasal spray (except egg proteins).
People who have had an extreme allergic reaction to any flu vaccine in the past.
Children and teens, 2–17, on aspirin or salicylate drugs.
Those whose immune systems are weak from drugs, immune diseases, HIV, or asplenia.
Caretakers or close contacts of severely immunocompromised patients who require isolation (or should stay out of their personal space for seven days after vaccination).
Pregnant individuals.
2 - 4 year old children who have asthma or had wheezing in the last 12 months.
Individuals with cerebrospinal fluid leaks.
People with cochlear implants.
Those who have recently received antiviral drugs for influenza (depending on the type and timing of the drug).

When to Consult a Healthcare Provider about the Nasal Spray Flu Vaccine

Some conditions may require you to discuss vaccination options with a healthcare provider to determine if the nasal spray flu vaccine is the best option for you. These conditions include:

Asthma in people who are 5 years old and older.
Background diseases that predispose to serious flu complications include chronic lung disease, heart disease, kidney or liver problems, neurologic or neuromuscular illness, blood disorders, metabolic disorders, and diabetes.
Moderate to severe illness (fever or no fever).
Guillain-Barré Syndrome after an earlier flu shot.

Priority Groups for Flu Vaccination During Shortages

When flu vaccine supplies are limited, priority should be given to:

Children between the ages of 6 months and 4 years.
Adults over 50, especially those aged 65 and over.
Chronically ill individuals with lung, heart disease (but not hypertension), kidney, liver, neurological, hematologic, or metabolic conditions.
People with compromised immune systems due to medication or diseases such as HIV.
Pregnant people and those under two weeks postpartum.
Adolescents and children 6 months to 18 years old who take aspirin or salicylate medications because they could get Reye syndrome.
Those who live in long-term care facilities.
American Indian or Alaska Natives.
Extremely obese individuals (BMI of 40 or greater).
Healthcare practitioners.
Families and caretakers of children under 5 and adults over 50 years old.
Home acquaintances and caregivers of people who are at risk for severe flu complications.

In summary, flu vaccination is a safe, effective way to shield individuals and communities from the yearly flu virus. If everyone is vaccinated, not only do they protect themselves, but everyone in their lives is better and safer for it.

Types of Flu Vaccines: A Deep Dive into Fluzone and High-Dose Vaccines

Fluzone High-Dose Quadrivalent vaccine by Sanofi Pasteur Inc. is a flu vaccine for people 65 years and older. It has four times the antigen of other flu vaccines and isolates four strains of influenza to help protect seniors. Together with Flublok Quadrivalent and Fluad Quadrivalent, it’s one of three senior-friendly vaccines that is recommended to the elderly.

Who Can Receive the Fluzone High-Dose Quadrivalent?

Fluzone High-Dose Quadrivalent vaccine is approved in the United States only for people 65 and older. It is not recommended for children or anyone with a severe allergy to vaccine components (except egg proteins). This age-based formula is designed to boost the immune system in the elderly, who are at greater risk of severe flu-related symptoms.

Why a High-Dose Vaccine for Seniors?

Elderly patients are more vulnerable to serious flu complications, such as hospitalization and death, because their immune systems become less effective with age. In the majority of flu seasons, the most flu hospitalizations and deaths are among those 65 and older. Fluzone High-Dose Quadrivalent is specially designed to evoke a more potent immune response in this age group and protects better than standard-dose vaccines.

Effectiveness and Safety

There is evidence to suggest that high-dose flu vaccines such as Fluzone High-Dose boost the immune system, reducing flu risk in older adults. The negative side effects (slight injection site pain, headache, muscle pain, etc.) are typically temporary. This increased response can be key to limiting the effects of flu illness in older adults, including its severity and duration.

Alternative Vaccines for People 65 and Older

Other favored flu vaccines, along with Fluzone High-Dose Quadrivalent, include Fluad Quadrivalent (which includes an added adjuvant for improved immunity) and Flublok Quadrivalent, a recombinant flu vaccine. If these preferred vaccines aren’t available, you can get any other age-appropriate flu vaccine.

Preventative Measures Beyond Vaccination

In addition to vaccination, these every day habits can also help reduce flu spread:

Avoid Close Contact: Stay away from sick people, and if you are sick yourself, limit your contact with others.
Cover Yourself: When sneezing or coughing, use a tissue to cover your mouth and nose, then dispose of the tissue immediately.
Masking: Masks may help reduce transmission, especially for those who are sick or at higher risk.
Hand Hygiene: Wash hands often with soap and water, or use an alcohol-based sanitizer if soap isn’t available.
Avoid Touching Face: Avoid touching your eyes, nose, and mouth to prevent germ spread.
Disinfect Surfaces: Regularly clean surfaces and objects that may be contaminated.
Improving indoor air quality: Opening windows or using air purifiers can also reduce virus exposure.

Consider Antiviral Medications if Prescribed

If you do contract the flu, your doctor may advise antiviral drugs to minimize the time and severity of the illness. Flu symptoms include fever, cough, sneezing, running nose, body aches, headache, cold, and tiredness. The best time to take antivirals is during the first two days of symptoms, but if delayed, they can still help at-risk individuals.

Antiviral Medications: Treatment Options for Influenza

Antivirals are a cornerstone in the fight against influenza and work with vaccines to curb the spread of the virus. These medications can not only cure the flu but can also be used to prevent it in certain circumstances.

Approved Antiviral Medications

For the flu season, these FDA-approved antiviral drugs are recommended:

Neuraminidase Inhibitors: These include oral oseltamivir (Tamiflu®), inhaled zanamivir (Relenza®), and intravenous peramivir (Rapivab®). They block the neuraminidase enzyme, affecting both influenza A and B.
Baloxavir Marboxil (Xofluza®): This oral drug targets influenza A and B by inhibiting viral replication through a different mechanism.

Antiviral Resistance

Resistance to these antivirals is relatively infrequent, but it can arise during or after treatment, especially in young children or the immunodeficient. For example, older antiviral medications such as amantadine and rimantadine are so resistant that they are no longer recommended.

Benefits of Early Antiviral Treatment

It’s been found that beginning antivirals as soon as possible – 24 hours to 48 hours after onset of symptoms – reduces the duration of illness, averts complications (such as pneumonia), and minimizes the chances of hospitalization, particularly in young children and older adults.

Priority Groups for Antiviral Treatment

Antiviral therapy should start immediately for people with suspected or confirmed influenza who:

Are hospitalized.
Show severe or worsening symptoms.
Are at higher risk for complications (e.g., older adults, young children, and those with chronic conditions).

Antiviral Options by Setting

Hospitalized Patients: Oral or enteric oseltamivir is recommended.
Outpatients with Severe or Progressive Flu: Oral oseltamivir is preferred.
Outpatients with Mild Symptoms: Based on age and health status, options may include oseltamivir, zanamivir, peramivir, or baloxavir.

Taking antivirals early on, especially for high-risk individuals, helps control the flu and decrease illness severity and complications.

Conclusion and Key Takeaways

There is no one way to mitigate influenza – it takes a multidimensional strategy to prevent it. If we learn the history of influenza pandemics, such as the one in 1968, it makes it clear why you should always be vigilant when it comes to managing flu seasons. Flu vaccination is still the best defense against flu, especially for vulnerable populations. Combining it with daily prevention measures – hand washing, air-flow regulation, staying out of close proximity to infected people – helps lower the flu’s transmission rate. For those who do fall ill, antiviral drugs provide additional protection by easing symptoms and limiting illness duration, particularly when started early. This integrated system of historical awareness, vaccination, prevention, and antiviral treatment is the best defense against influenza, keeping people and communities safe during flu season.