Couldn't find what you looking for?


As per the December 9 2009 update issued by the World Health Organization (WHO), more than 208 countries all over the world have reported confirmed cases of the swine influenza H1N1 2009 with a minimum of 9596 deaths related to the swine flu.

What is the current recommendation of the 2009 H1N1 flu vaccine?

The U.S. Food and Drug Administration (FDA) has approved the use of the new swine flu vaccine in the United States on September 15, 2009. Studies conducted by the National Institutes of Health (NIH) has revealed that within 10 days of the vaccination a single dose of H1N1 vaccine 2009 can create enough antibodies to protect one against the novel H1N1 virus. However, the fear of side effects has considerably restricted the use of this vaccine across all the regions.

The Centers for Disease Control and Prevention (CDC) has currently recommended that the following people should receive the flu shots on a priority basis:

  • Pregnant women
  • People who have infants younger than 6 months of age
  • Healthcare professionals with direct patient contact
  • Infants 6 months through young adults 24 years of age
  • Adults 25 through 64 years of age who are at higher risk for complications

A single dose of the vaccine for people who are 10 years and older and two doses (separated by a gap of 4 weeks) is currently being advised.

What are the side effects of the H1N1 2009 vaccine?

The rate of occurrence of side effects with the H1N1 2009 vaccine is similar to any other vaccine in general. The most common reaction noted to vaccinations such as the H1N1 2009 vaccine is the local allergic reactions. It has been estimated that about 1 in every 3 individuals who have been vaccinated may develop a sore arm. While some may develop redness in the injected area, others may develop a slight swelling. About 10-15% of the individuals who have taken the vaccine may develop symptoms such as tiredness, headache, or a low grade fever.

Further, the type of reaction may differ with the type of vaccine administered. Presently there are two main types of vaccines available: one that contains inactive virus proteins and the other that contains live viruses (in very minimal doses, just enough to build up the immunity while not causing the disease itself). The before mentioned symptoms are noted with the inactivated type of vaccination. Live vaccines that are commonly administered as nasal sprays can lead to reactions such as: runny nose, nasal congestion, cough, sore throat, low grade fever, irritability and headaches or muscle aches. Other symptoms rarely noted in children include wheezing and vomiting.

In rare cases the H1N1 2009 (as with any other vaccine) may lead to the development of severe allergic reactions that are commonly referred to as anaphylactic reactions. Such severe allergic reactions characterized by symptoms and signs such as difficulty in breathing or a sudden drop in the blood pressure can be sometimes fatal.

In highly rare cases, the administration of H1N1 2009 vaccine can cause the occurrence of a group of conditions known as the Guillain-Barre syndrome (GBS). This disorder which affects the nervous system is characterized by muscle weakness and paralysis that can be life-threatening at times. It has been said that 1 or 2 individuals out of every million people vaccinated can develop this syndrome.

Six cases of severe allergic reactions were reported in Canada in the month of November 2009 following the administration of the novel vaccine. It was reported that these reactions were noted in response to a particular batch of drugs and all affected individuals are recovering. These are some of the rare instances where a vaccination can cause more harm than benefit.

Although the risk of side effects still prevails, the WHO still recommends that it is the most effective way to fight against the novel H1N1 virus that has resulted in more than 9000 deaths till date.

What is thiomersal and what is the risk associated with it?

Thiomersal is a vaccine preservative which contains some amount of mercury in it. However, it has been reported that the type of mercury used in the thiomersal present in the current H1N1 vaccine contains ethyl mercury (in contrast to methyl mercury which tends to accumulate in the body) which is comparatively safe. No evidence of toxicity has been reported with the administration of thiomersal in infants, children, pregnant women and adults.

Who are at risk of developing side effects or adverse reactions to the vaccine?

Although the risk of adverse effects does not vary among all the individuals, some individuals have been declared to be at a higher risk of developing an adverse effect to the H1N1 2009 vaccine.

The CDC has declared that individuals who are allergic to eggs are at a higher risk of developing allergic reactions to the influenza vaccines including the H1N1 2009 vaccine. Individuals who have experienced any of the following symptoms are advised to consult a doctor before opting for the H1N1 2009 vaccine:

  • hives or swelling of the lips or tongue
  • difficulty in breathing or acute respiratory distress following the consumption of eggs
  • known hypersensitivity to eggs, including those individuals who have had an asthmatic reaction following exposure to egg or its products
  • individuals who have experienced any kind of allergic responses to egg or its proteins

Is the H1N1 2009 vaccine 100% safe?

No. None of the medicines or vaccines produced till date is reported to be 100% safe. All the synthetic medications have a few adverse effects the occurrence of which cannot be accurately predicted. Nevertheless, the risk of developing complications of the swine flu is considered much higher when compared to that from the vaccine itself. The individuals falling under the high risk group must consider getting vaccinated. However, individuals who are allergic to eggs need to consult their healthcare provider to verify whether they can receive the vaccine. Talk to your healthcare provider to weigh the benefits and drawbacks of the H1N1 2009 vaccine before getting vaccinated. Always remember to contact your healthcare provider in case you develop any reactions (although rare) to the H1N1 2009 influenza vaccine.