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Influenza

The influenza virus has been appearing in force in the New York City area since mid January. A pediatric office can tell that “influenza” has arrived when grammar school and high school students start coming in with fever and marked fatigue. Throughout the fall and winter, we’ve seen many younger children with respiratory illnesses especially croup and bronchiolitis. There has also been widespread outbreaks of vomiting and diarrhea (Norwalk and rota viruses). However, influenza has been very sporadic until the last couple of weeks.

What is “influenza”:

Influenza is a virus that is spread by air-borne respiratory droplets and hand contact. It attaches to the cells of the respiratory tract, causing watery eyes, nasal congestion, a scratchy throat, and coughing. It circulates throughout the world, and tends to peak in the United States in February.

One of the key symptoms of influenza is a profound sense of fatigue. Older children and adults will be able to remember exactly what time of day they started to feel “achy” or “tired.” The French term for influenza is “la grippe,” and the German term is “der gripp”–both referring to the feeling of weak muscles. When children have the flu, they act extremely tired and lay around the house like rag dolls. Babies sit limply in their parents’ arms. People describe having achy/tired muscles. This tiredness is a result of the body’s surge of gamma interferon, a naturally produced “anti-virus” substance that’s the main defense against influenza.

Many people might be exposed to a very small amount of influenza particles and fight them off without becoming ‘sick’. This is what happens to people who are “immune” or who picked up just a few viral particles at the time of contact. For other people, they might have some “laryngitis” and a mild cough. Babies might have croup or bronchiolitis. Asthmatics can experience a flare. Influenza “hits” different people in different ways. Many routine colds/coughs in children can actually be strains of influenza being “fought off” efficiently by the child’s top-notch immune system.

During childhood, people build up their immunity to various strains of influenza. When re-exposed to a similar strain years later, a person who built up immunity to a particular strain will only have a “cold” while other people around them are falling sick. People who are from large families build up immunity to a wide variety of influenza and other respiratory viruses by the time they go to college. They are much less likely to “get the flu” than the child who had a more “protected” early childhood. People who never had the opportunity to get exposed to influenza viruses in grammar school (when immunity is optimal) are much more likely to get sicker when they’re adults.

The reason the elderly get “sicker” from influenza is that they loose some of their memory influenza antibodies as they get older. Older people who are still working in public areas (i.e. teachers, doctors, nurses, politicians, waitresses) tend to not get sick with influenza because they keep getting “minute” exposures to various strains of flu each year.

Grandparents who see their grandchildren every day keep exercising their immune systems with every cough or cold that goes through the neighborhood. Those who are retired and only see the grandchildren for a scheduled visit, might get globbered by a new strain of influenza, especially if they give lots of hugs and kisses (allowing a larger dose of virions to be inhaled).

Important Note: Watch out for Secondary Bacterial Infections:

Influenza can cause miscropic injury to the respiratory lining, making it more “receptive” to pathogenic bacteria. This is why young children with influenza are more prone to bacterial ear infections and bronchopneumonias several days after the onset of influenza. Since the l990’s, most children in the United States have received the Prevnar vaccine against pneumococcus, as well as the HIB vaccine against Haemophilus influenza. This has decreased the incidence of serious secondary bacterial infections. However, a parent should still be vigilant about a child or adult who seems to be getting sicker about 4 days after the onset of flu.

Influenza itself is a virus and antibiotics are not needed. If a person goes to the doctor at the beginning of the fever, the doctor will not give antibiotics. However, with influenza’s ability to weaken natural defenses, it’s important to “GO BACK” to the doctor if the person is acting sicker after several days of illness.

A word about flu variants:

Influenza is a tricky virus in that it changes over time – shifting molecules on its outer surface in such a way that antibodies acquired from previous infections might not exactly ‘match’ a new strain. Some strains of influenza bear more of a resemblance to each other than others. An analogy of this would be a paisley print. Some are more similar than others in color and size/shape of the print.

Every year about two or three different strains of influenza might trickle through a community. The different flu viruses are classified according to the glycoproteins on the surface of the virus. One is called H for its ability to cause hemaglutination (clustering of blood cells in test tubes). The other is called N for neuraminidase (an enzyme). There are different subsets of H and N and the combination makes for a variety of different “strains.” People develop immunity to the different strains by either having the illness or being vaccinated against it. Each year the flu vaccine contains the surface coat pattern of three different strains of influenza

The CDC monitors influenza activity from several reporting hospitals around the country. This year, they have identified many strains of influenza A, A/Solomon, a recent antigenic variant of A/Caldeonia, but a few were A/Wisconsin. The influenza Bs have been of the B/Yamagata strain. Of note, this year’s influenza vaccine had A/Caledonia, making a pretty good match to the circulating strain, but the B component of the vaccine was B/Victoria instead of Yamagata.

Since 2003, influenza vaccine has become part of the rountine immunization schedule for infants over 6 months. It seems to be having a beneficial effect. Even if the vaccine doesn’t exactly match a circulating strain, it can help produce memory T cells that will help protect that child against strains that might emerge years later

Factors in the Spread of Flu:

Virion load:

The amount of exposure plays a role. People who inhale more influenza particles can become sicker than those who only inhale a few. Being in an enclosed space, and breathing more particles in per minute is likely to make a person more symptomatic.

Stress:

Being run down by stress and sleep deprived can weaken natural defense mechanisms. The classic example of this is the college student who stays up all night studying for exams, and then goes on partying Friday night.

A classic “high virion exposure” is a parent who’s preschool child climbs into the parents’ bed the night he/she starts spiking a fever. As the child sleeps in the parents’ bed, he/she can exhale lots of influenza particles into the face of the slumbering parents. This amounts to a “large” virion load.

Being “chilled”:

Influenza propagates more quickly in a chilled nasopharynx. Standing outside in the cold and feeling ‘chilled’, makes it easier for the flu virus to replicate. On the other hands, drinking something warm decreases replication rates of the virus. Drinking something warm after being outdoors in the cold helps decrease the viral load in the upper nostrils. Exercising in the cold is OK, because there is a resultant increase of nasal mucus. This is a natural protective response. Any recently acquired flu particles clinging to the nasal mucus can be blown out as “snot”. This is one reason why people doing winter sports don’t seem to get sick as often. However, the person should still avoid getting chilled waiting in long lines for a ski lift, or waiting for a bus. In the event someone has to wait outside for a bus, it’s good to have a scarf and hat, and if possible, sip on a warm liquid.

HOW TO TREAT THE FLU:

Keeping the Immune System Strong:

The immune system does most of the work by producing interferon and other immune substances that block the spread of the virus BUT make the person feel tired and sleepy. Antibiotics have no effect.

Vitamin C can help thin respiratory secretions, making them less viscous and inviting to bacteria. Echinacea (the American cornflower) has a substance which inhibits bacterial colonization. Giving the echinacea a couple of times a day helps defend the mucosal border while it’s weakened by the virus.

Many berries contain substances called anti-adhesins that diminish the ability of bacteria to cling to the mucous layer. Cranberries, blueberries and elderberries are among the berries in this group. Many other fruits, lemons, grapefruits, cherries, and grapes also have the antioxidants and bioflavinoids that help loosen phlegm and make the respiratory secretions less hospitable to secondary bacteria.

Rose hip tea, which is rich in flavinoids, is helpful in “loosening” coughs. A cough is an expected progression of the illness. Over the counter “cough and cold” medicines have no effect on how quickly the virus is dismantled.

Sleep:

During sleep, the immune system is especially efficient. It’s SO important for the person to be able to sleep as much as possible. A person with flu will feel draggy and exhausted through the day, but at night the person’s sleep cycle can be off-kilter. For many children and adults, nighttime sleep isn’t as deep and sustained. They might awaken in the middle of the night, or have trouble falling asleep at their regular time. This is an effect of the natural surge of interferon associated with flu.

Recovery Phase:

During the recovery phase, a person can feel very weak. Most people will feel their strength return after a week or so, however if they get exposed to another powerful respiratory virus within a couple of weeks, they often feel more “symptomatic”. This is because the influenza mobilized lots of T cells to the lungs and other tissues, and they are quickly able to induce a fever when rechallenged by another germ.

Also, sometimes influenza goes into a person’s muscles. This can give a sensation of ‘achiness’ in a muscle group. It is important for older children and teen atheletes to “not push themselves’, during the recovery phase. Their muscles have to recover. An athlete might not want to disappoint their team and want to jump back into full practice. The coach should understand that a person in the recovery phase from influenza might have actual microscopic damage to a muscle group. In the rare event that a small patch of cardiac muscle was temporarily affected, this could cause an irregular heart beat. Young people who had a bad case of influenza should only return to rigorous training after they are feeling completely well again for a week or two.