Source: Health Canada (http://www.phac-aspc.gc.ca/alert-alerte/h1n1/faq_rg_h1n1-eng.php )
H1N1 Flu Vaccine
Adjuvanted vaccine (NOTE: IN THE US THE ADJUVANTED VACCINE IS NOT BEING USED)
Q1. What is the difference between an adjuvanted and non-adjuvanted vaccine?
An adjuvanted vaccine is a vaccine that includes a substance that boosts an individual's immune system and increases their response to a vaccine. An unadjuvanted vaccine has no “booster” element.
Adjuvanted vaccines are included in common vaccines such as tetanus and Hep B. The adjuvant in Canada’s H1N1 flu vaccine is made up of natural ingredients such as water, squalene oil and vitamin E.
Q2. When was the last time an adjuvant was used in a vaccine?
Adjuvants are not new. They have been used for several decades to boost immune response to vaccines. Many of the commonly used vaccines in Canada contain an adjuvant. However, they have not previously been approved for use with influenza vaccines in Canada.
Q3. Are adjuvanted influenza vaccines safe for use?
The adjuvant used by GSK has been tested in approximately 45,000 people around the world and has been evaluated by Health Canada and other regulatory authorities as part of the review of the H5N1 vaccine in the pre-pandemic period. No significant safety concerns regarding the use of the adjuvanted vaccine were detected.
In June 2009, the WHO held consultations on the safety of adjuvanted influenza vaccines to review and discuss known and theoretical safety concerns and prospective vaccine safety evaluation. The outcome of the WHO consultation was that no significant safety concerns or barriers to evaluating or using adjuvanted vaccines for the current H1N1 virus were raised.
Q4. Does an adjuvanted vaccine pose a risk to pregnant women?
All evidence suggests that adjuvanted vaccines are just as safe as unadjuvanted vaccines; however there is no safety data for the use of adjuvanted vaccine in pregnant women. The WHO's Strategic Advisory Group of Experts (SAGE) recommended in July that pregnant women should receive non-adjuvanted vaccine where possible, but that an adjuvanted vaccine could be used if necessary.
General Vaccine Recommendations
Q5. Who should not receive the vaccine?
The following groups of people should NOT receive the H1N1 flu vaccine
* People who have had a previous anaphylactic (severe allergic reaction) to any element of the vaccine, OR
* People with a hypersensitivity to eggs ( e.g. hives, swelling of mouth and/or throat, breathing difficulty); OR
* People experiencing a high fever, OR
* People who have previously experienced Guillan-Barré Syndrome within 8 weeks of receiving a seasonal flu vaccine.
NOTE: The H1N1 flu vaccine is not approved for children under six months.
Q6. How long will it take after I receive the vaccine to have immunity against the virus?
After receiving the H1N1 flu vaccine, most people will start to develop immunity within 10 days with just one dose.
Q7. Can the H1N1 flu vaccine be administered at the same time as the seasonal flu shot and/or other vaccines?
The H1N1 flu vaccine can be administered along with seasonal influenza immunization and other vaccines.
Seasonal and H1N1 flu shots should be given in opposite arms. If an individual receives seasonal flu, H1N1 flu and pneumococcal vaccine in the same day, the seasonal flu shot and the pneumococcal vaccine should be given in one arm, and H1N1 flu vaccine in the other.
Adjuvanted and Unadjuvanted Vaccine Recommendations
Q8. Are there are serious risks with the adjuvanted vaccine?
No. There is no evidence to suggest that the adjuvanted vaccine is unsafe. Both vaccines have gone through extensive testing and review before being approved for use. However, there is no evidence available from clinical trials using adjuvanted vaccine in pregnant women or in children aged six months to three years.
The adjuvanted vaccine provides much stronger protection, however the Government of Canada ordered 1.8 million doses of unadjuvanted vaccine to offer pregnant women, since adjuvanted vaccine has not been widely tested in this group. The decision to purchase unadjuvanted vaccine for pregnant women is based on a desire to err on the side of caution.
Q9. Why didn't the government just buy enough unadjuvanted vaccine for everyone?
The WHO recommended countries use dose-sparing vaccines whenever possible. By developing an adjuvanted vaccine, we use less of the virus material (antigen), allowing us to immunize more people in a timely manner. The use of an adjuvant may also provide cross-protection against virus drift, which is common in influenza viruses. Virus drift occurs when the flu virus begins to change. Adjuvanted vaccine provides a broader spectrum of immunity as it protects against infection and severe disease even when the virus begins to change.
Q10. Is it true that adjuvanted vaccine gives a stronger immunity? If so, why isn’t everyone receiving the adjuvanted version?
Studies show that even the best unadjuvanted flu vaccines only protect six out of 10 people who get the shot. Experts believe an adjuvanted flu vaccine could boost protection rates to as high as nine in 10. Adjuvanted H1N1 flu vaccine is recommended for everyone over the age of six months, except pregnant women.
Unadjuvanted vaccine is recommended for pregnant women since adjuvanted vaccine has not been widely tested in this group. In cases where the unadjuvanted vaccine is unavailable and H1N1 flu rates are high or increasing in the community, women more than 20 weeks pregnant should be offered one dose of the adjuvanted vaccine.
All data to date indicates that adjuvanted vaccine is as safe as unadjuvated vaccine. The unadjuvanted H1N1 flu vaccine has a similar formula to the seasonal flu vaccine which has long been recommended for pregnant women.
Vaccine Recommendations for Children
Q11. The recommendation is that children between 6 months and 10 years old should get two half-doses of the adjuvanted vaccine. Why can’t they get one full dose?
The recommendation for two half-doses of vaccine in children under 10 is aligned with the seasonal flu recommendation. The seasonal flu recommendation is that children six months to 23 months receive two half doses of the vaccine, and children over the age of 23 months to 10 years who are receiving the vaccine for the first time should also receive two half doses of vaccine. This has been shown to give children the best immune response. Since the H1N1 flu vaccine is an influenza vaccine, the recommendation stands.
Additionally, reactions to the vaccine were higher in clinical trials for children who received a full dose as compared to those who received two half-doses.
Adverse Events following ImmunizationQ1. How are you going to be monitoring for adverse reactions once the vaccine is in use? What sort of reactions would be of the most concern?
Adverse events can happen with any vaccine, and we expect we will see primarily mild reactions to the H1N1 flu vaccine.
The monitoring for adverse effects from the H1N1 flu vaccine will be aggressive and tailored to seek out any potentially serious adverse events. Any serious events (including those that led to hospitalization or death) will be investigated.
Serious adverse events following immunization are rare. In any immunization campaign, from regular childhood vaccines to seasonal flu shots, the average reported rate of serious adverse events is about one for every 100,000 doses of vaccine distributed.
The majority of adverse events are minor reactions – like soreness at the injection site, or a slight fever – but sometimes, more serious events are reported. Serious adverse events are reactions that cause life-threatening illness, hospitalization, disability or death, like a severe allergic reaction, paralysis, or a seizure. These events are carefully investigated to determine if they are related to the vaccine directly, or if they were caused by an underlying health condition or some other reason.
Q12. Should children and adults expect the same type of side effects, if any?
The most commonly reported reactions after H1N1 immunization with the adjuvanted vaccine were minor and included pain, swelling and redness at the injection site. This is to be expected because the adjuvant helps the body develop a stronger immune response by increasing the inflammatory response.
Other commonly reported reactions were fatigue, muscle and joint pain, and headache. In younger children, a fever, drowsiness, irritability and loss of appetite were also reported in low levels.
Immunization is one of the most effective ways to prevent the spread of infectious diseases. The benefit of immunization – the prevention of serious illness and death – far outweighs any risk associated with being immunized.
Q13. What should be recommended for immunization for people with allergies to eggs?
People with a hypersensitivity to eggs, (e.g. hives, swelling of mouth and/or throat, breathing difficulty), should not receive the vaccine.
If you have a mild egg allergy, consult a healthcare provider before immunization. You may be able to be immunized with some additional precautions.
Q14. Is it true that there is mercury in the vaccine? How much mercury?
Both vaccines contain a small amount of thimerosal. Thimerosal is a form of mercury used in the H1N1 flu vaccine to stabilize it and maintain its quality during storage. Thimerosal is a different form of mercury than the mercury known to cause health problems. The amount in the H1N1 adjuvanted flu vaccine is much less than the daily limit recommended for environmental exposure to mercury. For example, there is significantly less mercury in the vaccine than you would find in a can of tuna fish.
Q15. Is it true that there is 10 times more mercury in the unadjuvanted vaccine? How can that be safe for pregnant women?
Yes, the unadjuvanted vaccine does contain 50 ug of thimerosal while the adjuvanted vaccine has only 5 ug of thimerosal. The 50 ug remains within the daily limit recommended for environmental exposure to mercury. There’s significantly less mercury in the vaccine than you would find in a can of tuna fish.
Q16. What are the key steps in developing a pandemic influenza vaccine?
The production of a pandemic vaccine cannot begin until the pandemic strain has been identified and candidate vaccine viruses are developed and tested by WHO certified laboratories. Candidate vaccine viruses are the starting material for vaccine development. The candidate vaccine viruses are then distributed to vaccine manufacturers for use in vaccine production. Many influenza vaccines, including the GSK pandemic vaccine, are produced by growing the influenza virus in eggs. For more information on the vaccine development process.
International Actions
Q17. The World Health Organization (WHO) has raised the pandemic alert level to Phase Six. What are these phases?
WHO currently identifies six stages of Pandemic Preparedness and Response.
Phase 1: Influenza viruses are circulating in animals, especially birds. No reports of animal viruses infecting humans.
Phase 2: Human infection by an animal influenza virus. Potential pandemic threat.
Phase 3: An animal or animal-human influenza virus has caused limited disease in people. Isolated human to human transmission may occur – but not widespread.
Phase 4: Verified human to human transmission of an animal or human-animal virus causing widespread or "community-level" outbreaks. Risk of pandemic is considered much higher but not a foregone conclusion.
Phase 5: Human to human spread of the virus is confirmed in at least two countries in one WHO region. It is likely that a pandemic is imminent. Time to finalize organization, communication, and implementation of planned mitigation strategies is short.
Phase 6: The Pandemic Phase. Community outbreaks in at least one country from a second WHO region – indicating that a global pandemic is underway. The Director-General of the WHO makes the decision about an elevation of pandemic phases based on reports from countries of the impact of disease.
Q18. The WHO has indicated that the overall level of severity of the pandemic to be moderate. What does this mean?
At this time, the WHO considers the overall severity of the pandemic to be moderate. This assessment is based on the clinical and epidemiological information available to WHO to date, as well as input from its Member States on the pandemic's impact on their health systems and more generally on their social and economic functioning. Essentially, this assessment reflects that:
* The overwhelming majority of patients experience mild symptoms and make a rapid and full recovery without the need for hospitalization or medical care.
* Overall, national levels of clinically severe or fatal cases of respiratory illness appear similar to levels seen during local seasonal influenza periods-- although in some local areas and institutions, high levels of disease have occurred.
* Overall, hospitals and health care systems in most countries generally have been able to cope with the numbers of people seeking care -- although in some localities, some facilities and systems have been stressed.
Q19. What other recommendations is the WHO making related to Phase Six?
The WHO is also recommending:
* No border closure. It will not be possible to stop the virus at the border, at ports or at airports. There is no evidence that these measures stop the spread of the disease, and they may be very disruptive for international traffic and trade.
* No restriction of travel. People who are infected with the virus and are capable of infecting others, may not show symptoms when travelling, so they cannot be identified from others who are not infected.
* Greater emphasis on providing care with a decreased emphasis on stopping the spread of the virus. Now that a pandemic has been declared,all governments will need to focus its resources on caring for those who fall ill.
Q20. Are all pandemics severe?
No. An influenza pandemic may be mild, moderate or severe. An influenza pandemic means the virus is spread easily between humans, and affects a wide geographic area. An influenza pandemic does not necessarily cause more severe illness than seasonal influenza.
