What is the pandemic (H1N1) 2009 virus?

This is an influenza virus that had never been identified as a cause of infections in people before the current H1N1 pandemic. Genetic analyses of this virus have shown that it originated from animal influenza viruses and is unrelated to the human seasonal H1N1 viruses that have been in general circulation among people since 1977.

Antigenic analysis has shown that antibodies to the seasonal H1N1 virus do not protect against the pandemic H1N1 virus. However, other studies have shown that a significant percentage of people age 65 and older do have some immunity against the pandemic virus. This suggests that some people in the older age group may have some cross protection from exposure to viruses that have circulated in the more distant past.

After early outbreaks in North America in April 2009 the new influenza virus spread rapidly around the world. By the time WHO declared a pandemic in June 2009, a total of 74 countries and territories had reported laboratory confirmed infections. To date, most countries in the world have confirmed infections from the new virus.

Unlike typical seasonal flu patterns, the new virus caused high levels of summer infections in the northern hemisphere, and then even higher levels of activity during cooler months in this part of the world.

The new virus has also led to patterns of death and illness not normally seen in influenza infections. Most of the deaths caused by the pandemic influenza have occurred among younger people, including those who were otherwise healthy. Pregnant women, younger children and people of any age with certain chronic lung or other medical conditions appear to be at higher risk of more complicated or severe illness. Many of the severe cases have been due to viral pneumonia, which is harder to treat than bacterial pneumonias usually associated with seasonal influenza. Many of these patients have required intensive care.

Who is at higher risk for severe illness?

How do people become infected with the virus?

The pandemic H1N1 virus is spread from person to person, similar to seasonal influenza viruses. It is transmitted as easily as the normal seasonal flu and can be passed to other people by exposure to infected droplets expelled by coughing or sneezing that can be inhaled, or that can contaminate hands or surfaces.

To prevent spread, people who are ill should cover their mouth and nose when coughing or sneezing, stay home when they are unwell, clean their hands regularly, and keep some distance from healthy people, as much as possible.

What can I do?

What are the signs and symptoms of typical infection?

Signs of the pandemic influenza are flu-like, including malaise, fever, cough, headache, muscle and joint pain, sore throat and runny nose, and sometimes vomiting and diarrhoea.

The majority of people with pandemic influenza experience mild illness and recover fully without treatment.

When should someone seek medical care?

People should seek medical care if they experience shortness of breath or difficulty breathing, or if a fever, and especially high fever, continues more than three days. For parents with a young child who is ill, seek medical care if a child has fast or labored breathing, continuing fever or convulsions (seizures).

Supportive care at home – resting, drinking plenty of fluids and using a pain reliever for aches and pains – is adequate for recovery in most cases. A non-aspirin pain reliever should be used for children or adolescents under age 18.

Why was WHO so worried about this flu when hundreds of thousands die every year from seasonal epidemics?

Seasonal influenza occurs every year and the viruses change each year – but many people have some immunity to the circulating virus that helps limit infections. Some countries also use seasonal influenza vaccines to reduce illness and deaths.

By contrast, the pandemic H1N1 was a new virus when it emerged and most people had no or little immunity to it. In addition, one of the lessons from history is that influenza pandemics can kill millions. Finally, there was no pandemic influenza vaccine at the outset.

The global impact of the current pandemic has not yet been estimated. Typically, the numbers of deaths from seasonal influenza or past pandemics are estimated using statistical models.

By contrast, the currently reported counts of over 16,000 deaths from pandemic H1N1 represent individually tested and confirmed deaths, primarily reported from countries with adequate resources for widespread laboratory testing. This approach has never been used to count seasonal or previous pandemic deaths and results in a significant underestimate.

A more accurate assessment of mortality from the pandemic, using statistical models, will likely be possible in about one to two years.

Who is more at risk of severe illness? What about other risks?

Who is more at risk of severe illness from pandemic (H1N1) 2009?

Some groups of people appear to be at higher risk of more complicated or severe illness, including:

  • pregnant women;
  • infants, and young children particularly under age 2;
  • people of any age with certain chronic health conditions (including asthma or lung disease, heart disease, diabetes, kidney disease or some neurological conditions);
  • people with severely compromised immune systems.

Currently, people age 65 or older are the least likely to be infected with the pandemic influenza, but those who do get sick are also at high risk of developing serious complications, just as they are from seasonal flu.

Are there special recommendations for pregnant women or other higher risk groups?

WHO recommends that pregnant women, or others at higher risk of severe illness and their caregivers, be vaccinated against pandemic influenza and take all the necessary precautions, including hygiene measures, to prevent the spread of illness.

Vaccination against the pandemic influenza is prudent for everyone to reduce chances of infection.

What about the risk of catching pandemic flu?

The pandemic influenza virus appears to be equally as transmissible and infectious among people as seasonal influenza viruses.

Studies to estimate how infectious the virus is among populations are in progress. Recent studies in the United Kingdom indicate that about one-third of school children in the country have been infected with the virus so far.

What about risk of death?

The majority of people with pandemic influenza experience mild illness and the overall risk of dying from this infection is low.

To date, the number of laboratory-confirmed deaths from the pandemic flu is over 16,000 cases but the real death toll is believed to be much higher.

It will only be possible to accurately estimate the total number of deaths, and death rates among certain groups, one to two years after the pandemic has peaked. The estimate will be calculated using statistical methods based on available data and medical records.

Vaccines for pandemic (H1N1) 2009

Influenza vaccines are one of the most effective ways to protect people from contracting illness during influenza epidemics and pandemics.

The pandemic influenza is a new virus, and virtually everyone is susceptible to infection from it. These vaccines will boost immunity against the new influenza, and help ensure public health as the pandemic evolves.

What is a pandemic?

A pandemic is the worldwide spread of a new disease.

An influenza pandemic occurs when a new influenza virus emerges and spreads around the world, and most people do not have immunity. Viruses that have caused past pandemics typically originated from animal influenza viruses.

Some aspects of influenza pandemics can appear similar to seasonal influenza while other characteristics may be quite different. For example, both seasonal and pandemic influenza can cause infections in all age groups, and most cases will result in self-limited illness in which the person recovers fully without treatment. However, typical seasonal influenza causes most of its deaths among the elderly while other severe cases occur most commonly in people with a variety of medical conditions.

By contrast, this H1N1 pandemic caused most of its severe or fatal disease in younger people, both those with chronic conditions as well as healthy persons, and caused many more cases of viral pneumonia than is normally seen with seasonal influenza.

For both seasonal and pandemic influenza, the total number of people who get severely ill can vary. However, the impact or severity tends to be higher in pandemics in part because of the much larger number of people in the population who lack pre-existing immunity to the new virus. When a large portion of the population is infected, even if the proportion of those infected that go on to develop severe disease is small, the total number of severe cases can be quite large.

For both seasonal and pandemic influenza, the highest levels of activity would be expected to occur in the usual influenza season period for an area. (In the temperate climate zones, this is usually the winter months, for example). But as was seen with the current H1N1 pandemic, pandemics can have unusual epidemiological patterns and large outbreaks can occur in the summer months.

What can I do to protect myself from catching pandemic (H1N1) 2009?

The main route of transmission of the pandemic influenza virus seems to be similar to seasonal influenza, via droplets that are expelled by speaking, sneezing or coughing.

You can prevent getting infected by taking the following measures:

  • keeping your distance from people who show symptoms of influenza-like illness, such as coughing and sneezing (trying to maintain a distance of about 1 metre if possible);
  • clean hands thoroughly with soap and water, or cleanse them with an alcohol-based hand rub on a regular basis (especially if touching surfaces that are potentially contaminated);
  • avoid touching your mouth, nose and eyes as much as possible;
  • reduce the time spent in crowded settings if possible;
  • improve airflow in your living space by opening windows;
  • practise good health habits (including adequate sleep, eating nutritious food, and keeping physically active); and
  • getting yourself (or family members age 6 months and older) vaccinated against the pandemic influenza, if possible.

What about using a mask? What does WHO recommend?

If you are not sick you do not have to wear a mask.

If you are caring for a sick person, you can wear a mask when you are in close contact with the ill person and dispose of it immediately after contact, and cleanse your hands thoroughly afterwards.

If you are sick and must travel or be around others, cover your mouth and nose.

Using a mask correctly in all situations is essential. Incorrect use actually increases the chance of spreading infection.

How do I know if I have pandemic influenza?

Today, since the H1N1 pandemic virus is now the dominant influenza virus circulating worldwide, most cases of influenza-like illness are likely pandemic influenza.

Typical symptoms to watch for include fever, cough, headache, body aches, sore throat and runny nose.

WHO advises health care providers to treat people with influenza-like illness based on their symptoms and the progress of their illness, and not to wait for laboratory confirmation of pandemic influenza. The pandemic H1N1 virus has already spread worldwide.

Regarding laboratory testing of cases, public health authorities and WHO partners continue to do selective testing of samples from patients with influenza-like illness to characterize outbreaks, monitor the virus and identify disease trends.

What should I do if I think I have the illness?

If you feel unwell, have a fever, cough or sore throat:

  • stay at home and keep away from work, school or crowds;
  • rest and take plenty of fluids;
  • cover your coughs and sneezes. If using tissues, make sure you dispose of them carefully. Clean your hands immediately after with soap and water or cleanse them with an alcohol-based hand rub;
  • if you do not have a tissue close by when you cough or sneeze, cover your mouth as much as possible with the crook of your elbow;
  • use a mask to help you contain the spread of droplets when you are around others, but be sure to do so correctly;
  • inform family and friends about your illness and try to avoid contact with other people;
  • If possible, contact a health professional before traveling to a health facility to discuss whether a medical examination is necessary.

Should I take an antiviral drug now just in case I catch the new virus?

In general, WHO does not recommend the use of antiviral drugs for prevention of pandemic influenza. Antiviral drugs should be taken if your health care provider advises you to do so.

In some instances national health authorities may provide antiviral drugs in advance to individuals at particular risk, or in certain public health situations.

These drugs are generally available by prescription only, though some countries have made special temporary arrangements during the pandemic to ensure that antiviral drugs can be made available quickly.

Caution should be exercised when buying antiviral drugs over the Internet.

What about breastfeeding? Should I stop if I am ill?

No, not unless your health care provider advises it. Studies on other influenza infections show that breastfeeding is most likely protective for babies – it passes on helpful maternal immunities and lowers the risk of respiratory disease. Breastfeeding provides the best overall nutrition for babies and increases their defense factors to fight illness.

When should someone seek medical care?

A person should seek medical care if they experience shortness of breath or difficulty breathing, or if a fever continues more than three days. For parents with a young child who is ill, seek medical care if a child has fast or labored breathing, continuing fever or convulsions (seizures).

Supportive care at home – resting, drinking plenty of fluids and using a pain reliever to reduce aches – 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.)

Should I go to work if I have the flu but am feeling OK?

No, you should stay home and away from work through the duration of your symptoms. This is a precaution that can protect your work colleagues and others.

Can I travel?

If you are feeling unwell or have symptoms of influenza, you should delay travel. If you have any doubts about your health, you should check with your health care provider.

Who is more at risk of severe illness? What about other risks?

Who is more at risk of severe illness from pandemic (H1N1) 2009?

Some groups of people appear to be at higher risk of more complicated or severe illness, including:

  • pregnant women;
  • infants, and young children particularly under age 2;
  • people of any age with certain chronic health conditions (including asthma or lung disease, heart disease, diabetes, kidney disease or some neurological conditions);
  • people with severely compromised immune systems.

Currently, people age 65 or older are the least likely to be infected with the pandemic influenza, but those who do get sick are also at high risk of developing serious complications, just as they are from seasonal flu.

Are there special recommendations for pregnant women or other higher risk groups?

WHO recommends that pregnant women, or others at higher risk of severe illness and their caregivers, be vaccinated against pandemic influenza and take all the necessary precautions, including hygiene measures, to prevent the spread of illness.

Vaccination against the pandemic influenza is prudent for everyone to reduce chances of infection.

What about the risk of catching pandemic flu?

The pandemic influenza virus appears to be equally as transmissible and infectious among people as seasonal influenza viruses.

Studies to estimate how infectious the virus is among populations are in progress. Recent studies in the United Kingdom indicate that about one-third of school children in the country have been infected with the virus so far.

What about risk of death?

The majority of people with pandemic influenza experience mild illness and the overall risk of dying from this infection is low.

To date, the number of laboratory-confirmed deaths from the pandemic flu is over 16,000 cases but the real death toll is believed to be much higher.

It will only be possible to accurately estimate the total number of deaths, and death rates among certain groups, one to two years after the pandemic has peaked. The estimate will be calculated using statistical methods based on available data and medical records.

Travel

Is it safe to travel?

Yes. But if you are ill, it is prudent to delay travel.

WHO is not recommending travel restrictions related to pandemic (H1N1) 2009.

The pandemic influenza virus has already spread around the world. There is no scientific reason to delay international travel to reduce spread of infection. The global public health response now focuses on minimizing the impact of the virus through prevention measures, more equitable access to appropriate medical care, and help to countries as they prepare and implement their public health plans.

Scientific research based on mathematical modelling shows that restricting travel would be of limited or no benefit in stopping the spread of disease. Historical records of previous influenza pandemics, as well as experience with SARS, validate this.

Returning travellers who become ill should contact their health care provider.

Does WHO recommend screenings at country entry and exit points to detect if ill people are travelling?

No. WHO does not believe entry and exit screenings would work to reduce the spread of this disease. However country-level measures to respond to a public health risk are the decision of national authorities, under the International Health Regulations 2005.

Countries that adopt measures that significantly interfere with international traffic (e.g. delaying an airplane passenger for more than 24 hours, or refusing country entry or departure to a traveller) must provide WHO with the public health reasoning and evidence for their actions. WHO will follow up with all of its Member countries on such matters.

Travellers should always be treated with dignity and respect for their human rights.

How can I protect myself from pandemic influenza when I am travelling?

Travellers can protect themselves and others by following simple prevention practices that apply while travelling and in daily life. Keep your distance from someone who is coughing and sneezing. Cover your coughs and sneezes. Wash your hands with soap and water, and avoid touching your eyes and mouth as much as possible. And again, do not travel if you are ill.

Is it safe to eat pork and pork products?

Yes. The pandemic (H1N1) 2009 virus has not been shown to be transmissible to people through eating properly handled and prepared pork (pig meat) or other products derived from pigs. The pandemic influenza virus is killed by cooking temperatures of 160°F/70°C, corresponding to the general guidance for the preparation of pork and other meat.

Source : WHO

Pandemic Influenza – Government of India

Do’s and Don’ts list

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