Flu prevention

No parent should have to experience the trauma of their child’s death. This is exactly what happened when the United States had its 1st pediatric influenza fatality in a young child in Florida. The child had not been vaccinated against influenza (aka flu) and neither were there any illnesses which could have made him/her more vulnerable to flu and its complications. 

Last year, over 80,000 people died of flu in the United States alone. We are in the middle of flu season right now and most of us are worried, or should be worried about getting the flu! This post will talk about how one gets the flu, how to avoid getting it or giving it to others, the different vaccines we have available and a bit about the microbiology (the science) behind the virus.

How many children die from flu each year?

  • flu related pediatric deaths became reportable in 2004
  • # of deaths per flu season have ranged from 37 to 185
    • A research study looked at pediatric flu deaths in years 2010 – 2016 and found that
      • half of these deaths were in otherwise healthy children;
        • about 78% were unvaccinated
    • 2009 pandemic: 358 children died of flu
    • 2017 – 2018: 185 children died of flu
      • About 80% of these children were unvaccinated against flu!
    • 2018 – 2019: 5 deaths, so far

How can you avoid getting flu?

  • get vaccinated
    • not a guarantee that you can avoid the flu
  • but if vaccinated individuals were to get the flu, it would be a milder version
    • recommended for everyone, 6 months and older
  • a strong recommendation, especially if you are in the high risk group for severe flu:
    • pregnant women
    • women who just gave birth and up to 2 weeks after
    • children younger than 5 years, especially younger than 2
    • adults 65 years and older
      • this includes residents of long term care facilities such as nursing homes, Alzheimer’s facilities etc.
    • those of American Indian and Native Alaskan ancestry
    • people with certain underlying medical conditions
      • best thing to do is to talk to your competent physician about the need for a Flu vaccine
  • follow infection prevention strategies
    • wash your hands
      • before touching your face
      • before eating
      • after coughing or sneezing into a tissue
    • limit close contact with sick people, if you cannot avoid it altogether
      • close contact is
        • a person within 6 feet of someone with flu, or
        • in the same room for a prolonged period of time as someone with flu, or
        • in direct contact with someone with flu
    • regularly clean and sanitize common use areas, especially this time of the year and especially if someone around you is sick with respiratory symptoms
      • examples include door knobs, elevator push buttons, common use items such as microwaves, photocopiers, etc.
    • hydrate well
    • refrain from smoking

When and how is flu contagious?

  • The infected individual is contagious even before he/she develops symptoms!
    • Not so easy to avoid being too close to someone who doesn’t even have symptoms yet!
  • The infected individual starts releasing viruses into the air…
    • from 1 day before symptoms appear, to 5 – 7 days after symptoms appear.

How does the patient with flu infect others?

  • It starts with the infected person breathing, talking, laughing, coughing, and/or sneezing
    • these activities generate saliva and mucus filled aerosols & droplets that carry infectious Flu viruses
      • these aerosols or droplets can land on
        • your face (eyes, nose or mouth), or
        • your hands (which you then use to touch your eyes, nose or mouth) or
        • on surfaces like door knobs, table tops, copy machines etc., which YOU then touch, followed by touching your face again
      • These activities introduce the Flu virus into your body.

How can the patient with flu minimize infecting others?

  • Stay home for 7 days from start of the illness or
    • 24 hours after fever AND respiratory symptoms are gone
  • Children may take longer than 7 days to stop spreading viruses
  • If it doesn’t interfere with your breathing, wear a facemask if you have to be out visiting the doctor or getting medication etc.
  • do not cough or sneeze into the air, or into your hands
    • cough or sneeze into a tissue
      • dispose tissue in a no-touch wastebasket with a lid
        • wash your hands
    • No tissue? Cough or sneeze into your upper sleeve:
      • the idea is to trap virus carrying droplets from circulating in the air or landing on other people’s faces or on surfaces
  • Avoid all in-person meetings
    • call in to your meeting

There is a right way to wash hands.

  • Wet your hands.
    • Use soap and water and work up a lather.
    • Scrub your hands for 20 seconds.
    • Scrub between your fingers, under your finger nails, your palms, backs of your hands, and your thumbs, an often neglected part of the hand when washing.
    • Rinse under clean, running water.
    • Use your elbow or a paper towel to turn off the faucet.
  • Dry your hands on a clean, paper towel or clean washcloth if you have one.
  • If there is no soap and water, use an alcohol based hand sanitizer (containing anywhere from 60% – 95% alcohol).
    • dispense enough sanitizer on the palm of your hand, to cover all areas of your hands
      • rub sanitizer between your fingers, under your finger nails, your palms, backs of your hands, and your thumbs
      • keep rubbing your hands until they are dry
    • do not wipe off hand sanitizer on a paper towel or washcloth

What will you do if you have flu and have to visit your doctor’s office or go to the hospital or urgent care center?

  • wear a facemask if it doesn’t interfere with your breathing
    • let the receptionist know you may have flu
  • if you are not wearing a facemask, cough and sneeze into a tissue
    • discard tissue into a no touch wastebasket with a lid
    • clean your hands
      • use soap and water OR alcohol based hand sanitizer (60 – 95% alcohol)
    • sit as far away from others as possible

Flu vaccines

  • Every year, we have access to flu vaccines that protect us against 2 Influenza A virus strains and 1 or 2 Influenza B virus strains.
    • Flu vaccines generally reduce our risk of flu by 40 – 60%

The right Flu vaccine if you are 65 or older

  • Fluzone high-dose
  • Fluad
    • both are inactivated vaccines (that means the viruses in the vaccines cannot grow)
    • both are designed to elicit a robust response from the elderly recipient and protect against 3 Flu virus strains (2 Influenza A and 1 Influenza B)

The right Flu vaccine If you want to avoid vaccines made in eggs

For the last 70 years or so, flu vaccines were made in eggs.

  • You might want to avoid vaccines made in eggs for 2 reasons:
    • You have egg allergies
    • Last year’s scientific finding which showed that when the Flu virus strain H3N2 is grown in eggs, it mutates (changes itself) in that environment, which means
      • the vaccine strain is so different that it does not provide effective immunity
        • resulting in an ineffective vaccine
      • H3N2 is in circulation again this year.
    • If you want egg free vaccines, your choices are:
      • Flublok, an inactivated vaccine for people 18 years and older
      • Flucelvax, an inactivated vaccine, for people 4 years and older
        • both protect against 2 Influenza A and 2 Influenza B strains

All the other types of flu vaccines for individuals 6 months to 65 years

  • There are 5 more inactivated vaccine choices in different formulations for different age groups, starting at 6 months of age and going all the way up to 65 years:
    • Afluria trivalent (protects against 3 Flu virus strains)
    • Afluria Quadrivalent (protects against 4 Flu virus strains)
    • Fluarix Quadrivalent
    • FluLaval Quadrivalent and
    • Fluzone Quadrivalent
  • The only live vaccine we have available is FluMist, for use in non-pregnant individuals, 2 – 49 years old.
  • FluMist was not used in the past 2 flu seasons because of
    • low vaccine efficacy
      • but, certain changes made to the vaccine this year may have made it more effective
    • The 2017/2018 flu season killed over 80,000 people in the United States.
      • We need to protect ourselves better this year.
        • Vaccination is considered to be the most effective approach to flu prevention.

How long does flu usually last?

  • Most people have mild symptoms and recover in 2 weeks or less.
  • Some people can have complications such as:
    • pneumonia, bronchitis, sinus infections, ear infections etc.
  • People with underlying medical conditions may get sicker.
    • Severe cases need hospitalization.
      • Some of the complications can cause death.

Flu symptoms appear abruptly and may include some or all of the following:

  • Fever or chills
    • not always present
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue
    • In addition to above symptoms, children may also show vomiting and diarrhea.

How many people get flu every year?

  • We don’t really know, since flu is not a reportable disease.
    • That means, when an urgent care center or doctor’s office diagnoses you with flu, they don’t have to report it to the local or state health department.
    • Besides, not everyone who gets the flu, actually seeks medical care or even gets tested.
  • The CDC uses data from flu surveillance AND some math modeling to estimate the # of flu infections every year
    • An estimated 9.2 million to 35.6 million people get the flu every year in the United States!

How many people are hospitalized due to severe flu every year?

  • This # is also an estimate that uses math modeling and #s from flu surveillance.
  • CDC estimates between 140,000 and 710,000 hospitalizations each year in the United States.

How many people die from flu each year?

  • Only flu deaths in children are reported to the CDC.
    • Flu deaths in adults are not reportable.
      • This # is an estimate that looks at deaths caused by pneumonia and influenza (P&I), and combines it with math modeling.
    • Deaths in the United States have ranged from a low of 12,000 (during 2011-2012) to a high of over 80,000 (during 2017-2018).

How can we treat flu?

  • Tamiflu® (oseltamivir)
    • oral drug
    • can treat both Influenza A and B viruses
    • treatment of uncomplicated flu
      • in patients 2 weeks old and up, if symptoms have lasted for or less than 2 days
      • although not approved by FDA, CDC and American Academy of Pediatrics recommends use in infants less than 2 weeks, if necessary
  • Relenza® (zanamivir)
    • inhaled drug
    • can treat both Influenza A and B viruses
    • treatment of uncomplicated flu
      • in patients 7 years and older, if symptoms have lasted for or less than 2 days
      • not to be used in people with compromised lung function: patients with cystic fibrosis, chronic obstructive pulmonary disease (COPD)
      • not to be used in people with allergies to milk protein
  • Rapivab® (peramivir)
    • single dose
    • intravenous shot
    • can treat both Influenza A and B viruses
    • treatment of uncomplicated flu
      • in patients 2 years and older, if symptoms have lasted for or less than 2 days
      • not used for prevention of flu
  • Xofluza® (baloxavir marboxil)
    • single, oral dose
    • can treat both Influenza A and B viruses
    • treatment of uncomplicated flu
      • in patients 12 years of age and older, who have had flu symptoms for or less than 2 days
      • not used for prevention of flu
  • Amantadine and Rimantadine
    • can treat only Influenza A viruses
    • There continues to be high levels of resistance (>99%) to these drugs among circulating influenza A(H3N2) and influenza A(H1N1)pdm09 viruses.
      • Therefore, these drugs are not recommended for treatment or prevention of currently circulating influenza A viruses.

What is post exposure prophylaxis (PEP) for flu and who should get it?

  • PEP is something you give as a preventative, once someone has had a definite exposure to a bug (Flu virus in this case)
  • Tamiflu® can be used for PEP in people 3 months and older
    • for children under 3 months of age, use is recommended only if the situation is critical
      • we just don’t have much data for the drug in this age group

Relenza® can be used for PEP in individuals 5 years and older.

Let’s consider a scenario we see every year, i.e. PEP when a high-risk person has a definite exposure to seasonal flu.

  • Typically, the elderly are at higher risk of severe flu and its complications.
    • A confirmed or suspected outbreak of flu is one with 2 or more residents who are ill.
      • If there is a flu outbreak in a nursing home for instance, all residents of that facility should receive antiviral drugs immediately.
        • even if they got vaccinated against flu
        • This is not dependent on lab results for flu.

Is it a good thing to vaccinate year after year?

  • I think this is a hard question to answer, because
    • the virus mutates from year to year, or even within the same year –
      • this means we are not really battling the same strains of virus every year.
    • There are also differences in the genetic makeup of individuals, leading to differences in the strength of the immune response against the different Flu vaccines.
  • While researchers try to answer this question, we are still faced with seasonal flu every single year.
    • In my opinion, vaccination + infection prevention = BEST FLU PREVENTION

How long does immunity last?

  • if person receives the Flu vaccine
    • immunity seems to last up to 6 months
  • if person gets the flu itself
    • immunity seems to last a lifetime
      • based on research done with survivors of the 1918 flu pandemic

Where are influenza viruses naturally found?

  • Influenza viruses are divided into A, B, C and D viruses, of which only A and B cause significant disease in humans.
    • Influenza A viruses are naturally carried in wild, aquatic birds such as ducks, geese, swans, gulls, and terns among others.
      • These Flu viruses normally do not cause disease in wild birds.
      • Flu viruses are found in the gut and respiratory tract of these birds.
        • Can spread to infect domestic poultry and other bird and animal species.
    • Influenza A viruses can also infect humans, pigs, and domestic poultry, among other species.
      • Every year, we have to deal with the seasonal Flu strain – not highly deadly, but highly contagious.
    • Influenza B infects only humans.

Why do we have a different Flu vaccine every year?

  • The answer lies in the nature of the virus and its genetic material.
    • The genetic information of the Flu virus is not made up of DNA (which is the genetic information in our cells), but is instead made up of RNA.
  • When Flu viruses try to make more copies of this RNA, they inevitably make mistakes because of the speed at which the copying (replication) is done.
    • The viral enzyme responsible for copying is quite tolerant of mistakes and doesn’t correct these mistakes when they are made.
      • Consequently, the virus makes mistakes, creating slightly different versions of the virus, which now allows it to avoid recognition by our immune system.
    • When these mistakes accumulate and result in higher diversity in the Flu virus, we see local, seasonal Flu outbreaks, which happens every 2 – 3 years or so.
  • There’s more!
  • Imagine 1 person getting infected with 2 different strains of the Flu virus. Now imagine those 2 strains infecting the same cell within that person! These 2 viruses will now be able to accumulate changes in its genes, using a mechanism called reassortment.
    • In order to do reassortment, the virus has to have its genetic information in segments.
      • The Flu virus carries its genes in 8 different segments (think of them as matchsticks).
    • Can this reassortment harm us?
      • Absolutely, yes!
    • Influenza A viruses can also infect humans, pigs, and domestic poultry, among other species.
      • Every year, we have to deal with the seasonal Flu virus strain – not highly deadly, but highly contagious.
      • There are parts of the world where we see a strain of virus that is highly deadly and highly contagious in birds – the Asian H5N1 strain of avian influenza, aka highly pathogenic avian influenza (HPAI) Asian H5N1
      • HPAI Asian H5N1 is regularly found in poultry in 6 countries: Bangladesh, China, Egypt, India, Indonesia, and Vietnam.
        • It is especially deadly to poultry.
      • It was 1st detected in 1996 in geese in China.
      • It was 1st detected in humans in Hong Kong in 1997.
        • Since 1997, it has been detected in wild birds and poultry in over 50 countries in Africa, Asia, Europe and the Middle East.
      • HPAI Asian H5N1 also happens to be highly deadly in humans.
        • But, it is not very contagious in humans.
          • It is extremely uncommon for humans to get it.
            • When a human does get HPAI Asian H5N1, it is not very contagious to other humans.
          • There are parts of the world where we see both HPAI Asian HFN1 AND the seasonal Flu strain.
            • IF both strains were to infect the same human and end up in the same cell, there is a possibility for reassortment to produce a new strain of virus that is highly contagious like the seasonal Flu strain and deadly, like the HPAI Asian H5N1!
              • IF THIS WERE TO HAPPEN, we would have a lethal pandemic on our hands.
            • To guard against this potentiality, we do a few things:
              • year round surveillance for flu activity
              • offer vaccines against 4 strains that seem to be highest in circulation
              • if reassortment were to happen and create a pandemic strain, it is more likely to have the involvement of one of the seasonal flu strains
                • yearly flu vaccines should give us some measure of protection, while we identify the precise pandemic strain and rush to vaccine production
              • Avian and human Flu viruses reassorted to give us 2 pandemics
                • 1957 pandemic
                • 1968 pandemic
              • Avian, human and swine Flu viruses reassorted to give us the 2009 flu pandemic.
              • At this time, we don’t really know what led to the creation of the Flu virus that caused the 1918 pandemic.
                • It killed 50 million people worldwide, with most deaths in the 15 – 30 age group.

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