Re: Frequently Asked Questions about the swine flu vaccine

[Guest guest]

Very interesting--about as conservative an approach as I've seen yet from the

" experts. "

And I had to laugh at this part: " It's expected the pandemic flu vaccine will be

as effective as seasonal flu vaccine, which is to say not 100 per cent. " Yes,

zero is not 100...

Winnie

Frequently Asked Questions about the swine flu vaccine

Vaccinations

>

> Frequently Asked Questions about the swine flu vaccine

> Updated Sat. Jul. 25 2009 2:49 PM ET

>

> Mulholland and Dr. Neil Rau

>

> CTV.ca, with the help of infectious disease expert Dr. Neil Rau,

> answers your questions about the coming swine flu vaccine.

>

> Should I get vaccinated against H1N1 swine flu?

> All Canadians will have the choice of whether or not to get the

> H1N1 flu shot; it will not be mandatory. Some groups, such as

> those with underlying conditions, obesity, asthma or who are

> pregnant, are thought to be more vulnerable to the virus and may

> want to get the vaccine first.

>

> Keep in mind that the virus causes only mild flu in most people

> and not everyone will need or want vaccination. In fact, some

> Canadians may have already been immunized against H1N1 thorough

> natural exposure to infection over the past few months. Others

> may choose to wait, to allow vaccine manufacturers to gather

> more safety and effectiveness data before everyone else is

> targeted. After all, the vaccine should be safer than the

> disease itself.

>

> If I've already had swine flu, will I need the vaccine?

> If you're certain you've had swine flu, you won't need the

> vaccine, at least for this coming season. The problem is that

> only a small number of people can be so certain. They are those

> who underwent lab testing, or who got ill as part of an

> outbreak, such as at a school or day camp where cases were

> confirmed through lab testing. Those people can presume that

> they also had the virus. However, most people will not know if

> they have had H1N1 unless an accurate blood test becomes

> available for this purpose.

>

> In future years, swine-origin H1N1 may " drift, " and prior

> infection may not offer immunity against any new version of the

> virus. By that point, we will have a much clearer idea of the

> seriousness of H1N1 and the safety of the vaccine to decide on

> the need for ongoing wide-scale vaccination.

>

> Haven't there been delays in manufacturing the vaccine?

> As the World Health Organization and other manufacturers

> announced in mid-June, the first " seed strains " of the virus

> they provided to manufacturers produced low yields in the

> manufacturing process - less than half of what they get with

> seasonal vaccine strains. The WHO says its laboratory network is

> generating further strains that may provide higher yields.

>

> Flu vaccine production is inherently slow, because it begins

> with growing viruses in fertilized chicken eggs. For every shot,

> one egg has to be infected with the virus, where it then

> replicates before being extracted and purified into a vaccine.

> But if yields continue to remain low, multiple eggs need to be

> used, which slows down production and may result in a limited

> vaccine supply.

>

> What are some strategies to use if the vaccine yield remains

> low?

> One way to work around the problem would be to use adjuvants,

> which are chemical additives added to some vaccines to ramp up

> the response the immune system generates to a vaccine. With

> adjuvants, less pure vaccine antigens are needed.

>

> But the problem is that flu vaccines don't normally use

> adjuvants. That means manufacturers couldn't use the fast-track

> vaccine approval system that allows seasonal flu vaccines to be

> tweaked every year with small adjustments to the strains. Adding

> an adjuvant would make the pandemic vaccine fundamentally

> different from seasonal flu vaccine, and would require a new

> licence. It would also slow down the approval process since it

> would likely mean more clinical trials to assess safety.

>

> While the U.S. may choose not to use adjuvants to speed the

> approval process, Dr. -, head of the Public

> Health Agency of Canada, has said that Canada would likely use

> an adjuvanted pandemic flu vaccine, given the problems with

> production and the WHO's request that manufacturers use " antigen

> sparing strategies. "

>

> Another approach is to give the vaccine " intradermally, " that

> is, under the skin, rather than intramuscularly. This would

> allow doctors to use a lot less vaccine to produce a stronger

> immune response. In this way, more people could still get the

> vaccine if yields remain low.

>

> The third approach would be to offer the vaccine selectively, to

> only those who need it most.

>

> When is the vaccine likely to be ready?

> The hope had been that the vaccine would be ready for October,

> but that's changed with the production delays. Because the total

> production and testing time is about 19 weeks, an H1N1 vaccine

> may be available in November in a best case scenario, according

> to the Public Health Agency of Canada says on its website.

>

> Other countries - perhaps those that decide not to use adjuvants

> - may have a vaccine available sooner, depending how their

> manufacturers fare with production.

>

> Who is making the swine flu vaccine for Canadians?

> GlaxoKline is the vaccine manufacturer under contract by

> the government of Canada to supply the country with a pandemic

> influenza vaccine. GSK already supplies the majority of the

> government's seasonal flu vaccines.

>

> The Government of Canada purchases flu vaccines on behalf of the

> provinces and territories. The vaccine is then made available at

> public health clinics and doctors' offices according to

> provincial immunization programs.

>

> How safe is the vaccine expected to be?

> The companies making H1N1 flu vaccine have been making seasonal

> flu vaccines for years and have good track records of safety.

> But they are unlikely to undertake the necessary, complicated

> safety studies themselves, and will likely work alongside

> government bodies that will fund the work.

>

> Vaccine experts will test various doses of the H1N1 vaccine to

> see how large a dose is needed for protection and how many

> doses. They will also test whether people with egg allergies can

> be offered the pandemic flu vaccine. They might also test

> whether an adjuvant affects the vaccine's effectiveness and

> safety, and how the vaccine affects someone who has already had

> H1N1 infection.

>

> The adult testing process has already started in some parts of

> the world and is due to start in the U.S. in mid-August. The

> process would likely take about six weeks. If early information

> from those trials suggests the vaccines are safe, similar trials

> in healthy children aged six months to 17 years would begin

> next.

>

> Large-scale, long-term tests of safety won't be feasible if the

> vaccine is to be administered promptly. Therefore, Health Canada

> has said it will work with other world health agencies to

> monitor the safety and effectiveness of the vaccine in post-

> market surveillance, and " to ensure the timely communication of

> any potential adverse events following immunization. "

>

> Many remember the rare neurological events that followed the

> hastily prepared, swine-derived flu vaccine in 1976. The World

> Health Organization's flu chief, Keiji Fukuda, has said there

> must be no doubt over the safety of swine flu vaccines before

> they are given to the public.

>

> How effective will the vaccine be?

> It's expected the pandemic flu vaccine will be as effective as

> seasonal flu vaccine, which is to say not 100 per cent.

>

> In years when the strains of the flu virus in the seasonal

> vaccine have been a good match for the dominant strains

> circulating in the community, the vaccine has been shown to

> reduce chances of infection by 70 to 90 per cent in healthy

> adults. The vaccine may be somewhat less effective in elderly

> persons and very young children. Fortunately, the elderly are

> not targeted to receive the vaccine because of their pre-

> existing immunity.

>

> It should be noted that it takes about two weeks after

> vaccination for antibodies to develop in the body and provide

> protection, so a recipient is still at risk for infection in the

> two weeks after a shot.

>

> It remains to be seen whether " booster " flu shots will be needed

> with this pandemic flu strain. This H1N1 strain may also begin

> to drift over time, such that a slightly different version of

> vaccine will be needed in the future. Or, H1N1 may " die out " as

> the main cause of flu after a few more seasons, and future years

> may not justify the need for an H1N1 vaccine.

>

> Will seasonal flu vaccine protect against the new H1N1 strain?

> No. The CDC's Dr. has said tests have confirmed that

> people who have received seasonal flu vaccines in the past have

> little or no immunity to the new H1N1 virus.

>

> Seasonal flu shots protect against one strain of influenza B and

> two of influenza A -- including a human subtype of H1N1. But the

> new swine flu is a swine-derived H1N1. So, despite the

> similarity in names, the regular flu shot won't offer protection

> against the new H1N1 virus.

>

> But since the usual seasonal influenza viruses are still

> expected to cause illness this winter, Canadians are still

> encouraged to get their seasonal flu shot this fall. Health care

> workers should particularly heed this advice.

>

> Can the seasonal vaccine and the novel H1N1 vaccine be given at

> the same time?

>

> We're not yet sure, but probably yes. Clinical trial results

> will be needed to ensure that the immune response to H1N1 is not

> blunted by giving the seasonal flu vaccine at the same time. In

> any event, the seasonal vaccine is expected to be available

> earlier than the H1N1 vaccine - perhaps much earlier.

>

> Who will be able to get the H1N1 vaccine?

> The current expectation is that there will be enough vaccine for

> all Canadians who want it. But if supplies are low, the WHO

> recommends that health-care workers be given first priority to

> receive the shot, to ensure they will be able to keep health-

> care systems functioning should there be a surge of communities

> illnesses that stress the health care system. Thus far,

> significant and severe community illness has not been seen with

> H1N1.

>

> A panel of experts who advise the WHO on vaccine issues suggests

> countries should also prioritize pregnant women, children and

> healthy young adults as well. Those groups seem to be among

> those hardest hit so far by the pandemic virus, while older

> adults have been less likely to fall ill.

>

> It will be interesting to see how many Canadians opt for the

> pandemic flu vaccine. In Ontario, which introduced a free flu

> vaccine program nine years ago, the participation rate is about

> 42 per cent, the highest in the country, according to Statistics

> Canada.

>

>

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