Swine Flu (H1N1): What You Need to Know

I track flu and other public health threats.  I write this blog entry to help anyone who asks the question, "What do I need to know about swine flu?" or "What can I do to protect myself from pandemic flu?" I rely heavily on the Australian public health information system because it seems to be more proactive about prevention — educating and putting responsibility for preventive measures on the public.  I have mainly cut and pasted information from sources that I deem reliable, with links to each source so that you can read the information for yourself.  I hope you this useful — if you do, please let me know by leaving a comment.   

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H1N1 IS A PANDEMIC FLU

As school returns to fall session in the USA, a new, pandemic flu is sweeping through campuses across the nation. In the first week of classes, Georgia Tech had 150 suspected cases; the University of Kansas had 200 stricken with it. Source: Associated Press via WDSU News   In Aiken County, South Carolina, 52 students were sent home with flu symptoms during the first week of school. (Eleven of those students were confirmed to have been infected with pandemic flu, though at this time further testing for H1N1 has ceased due to its widespread incidence in the population.) Source:  Aiken Standard Newspaper

ORIGIN AND SPREAD OF THE VIRUS WORLDWIDE

It is speculated that the virus now known colloquially as “Swine Flu” originated about ten years ago in Mexico. It became more widespread in December 2008 and was declared pandemic in the summer of 2009. Source: International SOS Clinics It has now become the dominant influenza strain throughout most of the world. Source: WHO

The term “swine flu” does not mean that humans can catch the flu from eating pork. Rather, this is a virus that has mutations that originated from swine. Source: SC DHEC  Technically speaking, the name of the disease is "Influenza A (H1N1)". With declaration of pandemic status, the proper term for the illness is "Pandemic (H1N1) 2009". (The term "pandemic (H1N1) 2009" refers to the disease, and the term “pandemic H1N1/09 virus" refers to the agent.)

At this time, Pandemic H1N1 flu virus is widespread worldwide, but especially so in the Americas. Indeed, there are so many cases that attempts to keep count of numbers have been discontinued in the USA.  Source: USA CDC

Confounding matters, it is widely reported that somewhere between 30% and 50% of swine flu infections may not induce fever.  Because fever has for so long been a main indicator of flu, many infected students may remain in school, thinking they do not have swine flu.  Further, health departments may refuse to test students for H1N1 because they have no fever. Source: NY TimesRecombinomics, Inc.

For a flu tracker map, click HERE

SEVERITY OF ILLNESS

Most cases of H1N1 are mild. An odd feature of the new virus is the lack of fever in a significant proportion of documented cases, even after some patients become seriously ill. Wall St. Journal  In Chile about half of those affected had no fever. In Mexico City, about a third had no fever, and similar patterns have been reported in other places. Source: NY Times 1 NY Times 2.  In the US, fever is used in the case definition, so patients presenting without fever are not even tested.  Coincidentally, the official USA numbers show that 93% of lab confirmed cases have a fever.  However, this is almost certainly linked to the case definition, because in the USA the standard definition of influenza includes a fever.   Recombinomics, Inc.

The absence of fever in H1N1 can be significant in several respects. Absence of fever among substantial proportions of patients, when fever is specified in the definition, can cause serious underestimation of case totals. For example, the CDC by definition only characterizes symptoms formally as "influenza-like illness" (ILI) if there is a fever of 100 degrees or more, body aches, fatigue and a cough or sore throat for which there is no other known cause. Source: USA CDC Secondly, absence of fever limits the usefulness of thermal scans to identify people who have the virus and thus control the pandemic.  This eliminates a handy means of selecting individuals for segregation or quarantine.  Thirdly, absence of fever removes a traditional identifying symptom for flu and therefore keeps infectious individuals in the public environment (e.g. school or workplace).  Lack of identification and separation from the general population thus leads to increased exposure, school clusters, and faster spread throughout the population. Source:  Recombinomics, Inc.

In contrast to the mild cases, there is also a severe form of H1N1 which directly attack lung tissue.  Clinicians from around the world are also reporting that there is a very severe form of H1N1, also found in young and otherwise healthy people. In these patients, the virus directly infects the lung, causing severe respiratory failure. Saving these lives depends on highly specialized and demanding care in intensive care units, usually with long and costly stays. 

To date, most severe cases and deaths have occurred in adults under the age of 50 years, with deaths in the elderly comparatively rare. This age distribution is in contrast with seasonal influenza, where around 90% of severe and fatal cases occur in people 65 years of age or older.

RISK FACTORS FOR SEVERE FORM

Risk factors for the more severe form of the H1N1 infection include obesity, asthma, cardiovascular disease, and diabetes. Pregnant women are also at higher risk.  Source: WHO, NY Times

Minorities and indigenous populations have a particular, increased risk for the severe form. Black and Hispanics are four times more likely than Caucasians to need to be hospitalized for pandemic flu. Source: Associated Press The causes of this difference are not known, though it is suspected there may be a relation to overall health and increased risk factors associated with poverty.  Source: WHO

School Children:  To date, highest attack rates are seen in school children. This is expected for a novel influenza virus, especially considering children’s relatively poor hygiene and lack of social distancing. The virus will likely move upwards into the older siblings and parents and, in later successive waves, to the grandparents. Source: International SOS Clinics

H1N1 and HIV: Early data suggests that people co-infected with H1N1 and HIV are not at increased risk of severe or fatal illness, provided these patients are receiving antiretroviral therapy. In most of these patients, illness caused by H1N1 has been mild, with full recovery. http://www.who.int/csr/disease/swineflu/notes/h1n1_second_wave_20090828/en/index.html

The Aged:  Unlike seasonal flu, older people appear to have less risk. It is theorized that people over the age of 65 may have some natural immunity, perhaps due to circulation of a swine flu virus in the 1950’s. However, due to genetic drift (mutation) of the current virus, the benefit of this immunity is expected to last only one to two years as the virus mutates into new forms. Source: WHO

HOW SWINE FLU IS SPREAD

H1N1 flu is an airborne virus.  It is most likely spreading from person to person in the same way seasonal flu viruses spread: through infectious respiratory droplets. These droplets are expelled when an infected person coughs, sneezes or talks. These droplets can spread about 1 to 2 meters (3-6 feet) before they fall. If they get into a healthy person’s nose or mouth, the person can get infected. (This is called "direct contact".)

Hand hygiene:  Hand hygiene is essential in the reduction of transmission of infectious agents. Hand hygiene includes washing hands with soap and water or cleaning hands with alcohol based products (gels, rinses, foams) that can be used without water.

• If your hands are visibly dirty with respiratory secretions (phlegm, spit), you need to wash them with soap and warm water, scrubbing your wrists, palms, fingers and nails for 15-20 seconds, and then dry with a clean dry towel or paper towel.

• If there is no visible dirt, you could use an alcohol-based hand rub.

• In general, try to keep your hands away from your face.

( source: Australian Dept of Health )

People can also get infected through "indirect contact". The droplets expelled by a sick person can contaminate objects. Flu virus can live on hard surfaces for hours, as long as 2 days. It can get onto people’s hands when they touch something contaminated, such as doorknobs, keyboards, counters, etc. If the person then touches his or her eyes/nose/mouth with their hand, the virus can enter their body.

Influenza may also spread via "aerosol" transmission, where the where the virus floats in the air and infects people. This is particularly possible in crowded places. This is not thought to be a frequent mode of flu transmission, and may only happen in unusual circumstances where ventilation is poor.

Cough and sneeze etiquette:  If you cough or sneeze, you should

• Wear a Facemask if you are coughing and sneezing

• Cover your nose and mouth with a disposable tissue rather than your hands.

If there are no tissues available, cover your nose and mouth with your upper arm rather than your hands. Wash your upper arm (or sleeve) as soon as practical if you have sneezed or coughed into it.

• Dispose of used tissues in the nearest bin.

• Wash your hands afterwards or after touching used tissues.

(source:  Australian Dept of Health)

Any secretions and bodily fluids of someone with H1N1 are considered potentially infectious. This includes vomit, diarrhea and mucus.  (source:  International SOS Medical Clinics)

SYMPTOMS OF SWINE FLU

Initial symptoms of H1N1 are similar to the symptoms of "regular" (seasonal) flu. These are:  fever, body aches, tiredness, headache, runny nose, sore throat and cough. With this virus, people also often have vomiting and diarrhea. Some infected people develop a severe illness, which can include pneumonia and difficulty breathing. Australian CDC

As noted above, however, somewhere between 30% and 50% of cases do not have a fever.  The atypical symptoms with the H1N1 flu, with lack of fever being common, as well as the presence of diarrhea, both of which are unusual in seasonal influenza, are likely to confuse practitioners and lead to delays in diagnosis. Source: Wiki-medpedia (Dr. Richard Wenzel) If you have all the symptoms of flu but no fever, assume that you are contagious and use appropriate precautions to avoid infecting others! 

The incubation period appears to be between one and seven days. People can spread the germs for flu before they begin to feel symptoms and until after symptoms completely disappear.

WHAT TO DO IF YOU GET FLU

Stay at home and keep away from work, school and crowded areas or public gatherings until symptoms have resolved. If medical attention is required, people should consult a medical practitioner by telephone;

Avoid contact with other people where possible;

Cover nose and mouth when coughing and sneezing and, if using tissues, make sure you dispose of them carefully;

Clean hands regularly, and immediately after coughing or sneezing with soap and water or cleanse them with an alcohol-based hand rub;

Alleviate the symptoms: rest, drink plenty of fluids and use a pain reliever for aches. This is adequate for recovery in most cases. A non-aspirin pain reliever should be used by children and young adults because of the risk of Reye’s syndrome

At the present time, the antiviral drugs oseltamivir and zanamivir are effective against the H1N1 virus and reduce the incidence of severe respiratory complications. Source:  WHO. Because these drugs must be administered within 24 to 48 hours of onset of symptoms to be effective, treatment should not be delayed. At present, only a handful of pandemic viruses resistant to oseltamivir have been detected worldwide, despite the administration of many millions of treatment courses of antiviral drugs. Source:  WHO The pandemic flu is resistant to a second class of antivirals, the M2 inhibitors. Source:  Ibid, Australian Dept of Health

Worldwide, most patients infected with the pandemic virus continue to experience typical influenza symptoms and fully recover within a week, even without any form of medical treatment. Healthy patients with uncomplicated illness need not be treated with antivirals.  Source: WHO   Severe cases, however, should be treated immediately with antiviral medications.

DANGER SIGNS

Clinicians, patients, and those providing home-based care need to be alert to danger signs that can signal progression to more severe disease. As progression can be very rapid, medical attention should be sought when any of the following danger signs appear in a person with confirmed or suspected H1N1 infection:

  • shortness of breath, either during physical activity or while resting
  • difficulty in breathing
  • turning blue
  • bloody or coloured sputum
  • chest pain
  • altered mental status
  • high fever that persists beyond 3 days
  • low blood pressure.

In children, danger signs include

  • fast breathing or trouble breathing,
  • bluish or grey skin color,
  • not drinking enough fluids,
  • severe or persistent vomiting,
  • lack of alertness,
  • difficulty in waking up,
  • being so irritable the child does not want to be held,
  • little or no desire to play, and
  • flu symptoms seem to improve but then return. 

Sources: WHOUSA CDC

USE OF FACE MASKS

If you are not sick you do not have to wear a facemask. If you are sick, you should wear a facemask when seeking medical attention or when in close company of vulnerable people.

A household member should wear a facemask if they need to come within one meter (three feet) of an ill person who is not able to wear a mask, particularly if they are in a vulnerable group. 

If you choose to wear a mask you should follow the Facemask procedures below. Wearing a facemask incorrectly or removing or disposing of it improperly can contaminate the wearer’s hands, mouth or eyes with virus, possibly resulting in exposure of the wearer or others to the virus. Sources:  Australian Dept of Health and Aging (Note: The USA CDC seems not to condone use of Facemasks, for reasons unknown to me.   See USA CDC facemask page.  I notice from living in Asia that use of Facemasks as a matter of courtesy to prevent sharing of germs is much more prevalent in Asia.  I speculate this is due to having significantly higher population density, as well as Asian culture in general seems more focused on prevention of illness while American culture seems more focused on intervention after illness.)

A PERSON WITH SWINE FLU SHOULD ISOLATE THEMSELVES AS MUCH AS POSSIBLE

A person ill with flu should be isolated in a different area of the house from the rest of the family. One member of the household should be designated to care for the affected individual. The person caring for the affected individual should use fastidious hygiene, including hand washing and proper use of a face mask. If possible, ventilate the ill person’s room with outside air and disinfect surfaces and doorknobs. 

WHAT YOU CAN DO TO PROTECT YOURSELF FROM SWINE FLU

Wash your hands thoroughly and often. Cover your cough with your sleeve, not your hand. Stay home if you’re sick. Stay away from people who are sick. Eat a healthy diet and get plenty of rest

You can prevent getting infected by avoiding close contact with people who show influenza-like symptoms (trying to maintain a distance of about 1 meter (3 feet) or more, if possible) and taking the following measures:

• Avoid touching your mouth and nose;

• Clean hands thoroughly with soap and water, or clean hands with an alcohol based hand rub on a regular basis;

• Do not visit people who have the flu unless it is absolutely necessary; Eat a healthy diet; get plenty of rest;

When someone in the house has flu it is important that:

  • they clean their hands regularly;
  • the household environment is regularly cleaned; surfaces should be cleaned with disinfectant
  • the person with illness stays home and avoids contact with others; and
  • the person with illness wears a surgical mask or other appropriate face coverings, if possible, when others are in the room,
  • and stays at least 1 meter (3 feet) distant from others.

Sources: State of SC DHEC , Australian Dept Health & Aging

VACCINATION

Significant quantities of H1N1 vaccine will not be available until October. Source: Reuters News Service .  In the northern hemisphere, this is well into the expected fall/winter epidemics.  Source: International SOS Medical Clinics

When H1N1 vaccine is available, it will only protect against H1N1; it will not protect against ordinary seasonal flu. Therefore, individuals who seek to be protected against flu will need to be vaccinated separately for seasonal and pandemic flu. It is not yet known whether the pandemic flu vaccine will require one shot or two. Source: Australian Dept Health  Thus, complete flu protection will require either two or three separate shots.

WORKPLACE PRECAUTIONS

Workplaces should focus on:

• Promoting good hand, respiratory hygiene etiquette and other infection control

practices..

• Ensuring that materials needed for hand and respiratory hygiene are readily

available in the workplace (e.g. tissues and receptacles for their disposal, soap and

hand washing facilities and/or alcohol-based hand sanitizers).

• Encouraging and supporting staff members with acute respiratory illnesses to stay

at home until they are well (that is until their symptoms have completely resolved).

• Encouraging visitors/customers with acute respiratory illness to stay away from the

workplace until they are well (that is until their symptoms have completely

resolved).

SWINE FLU IN THE FUTURE

Waves of anxiety and public concern are affecting social patterns in affected countries. High levels of public concern can lead to disproportionate and discriminatory behavior. Source:  International SOS Clinics .  This in itself could be very disruptive to business and trade, travel, and daily pursuits. This type of disruption was evidenced by the reaction to SARS in 2004. It is hoped that disruption will be minimized by a combination of public education and effective control and treatment of the disease.

A serious concern is the possible mixing of genes from H1N1 (Swine Flu) with H5N1 (Bird Flu). Because H5N1 is currently much more deadly to humans than H1N1, any mixing of genes which resulted in increased human to human transmissibility of H5N1 could be hugely threatening. A much less threatening scenario is if the H1N1 outbreak caused suppression of H5N1 virus outbreaks. Source:  International SOS Clinics

In the final analysis, few of the 6 billion people who live on Earth will escape the H1N1 pandemic, but such global spread will take 3-4 years. A combination of sensible behavior, social distancing, hand and surface hygiene and the use of antivirals and vaccines to protect vulnerable groups should suppress mortality to that experienced in the last pandemic of 1968. Source:  International SOS Clinic

REFERENCES

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2 Comments

Filed under Health and wellness

2 responses to “Swine Flu (H1N1): What You Need to Know

  1. Rosemary

    Helpful and useful information!

  2. Kelley

    Good article. Thanks!

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