Understanding swine flu

Health authorities worldwide are insisting the swine flu vaccine is safe and are urging everyone to get the jab against the virus that has killed four people in Malta. Despite this reassurance, people remain concerned about possible side-effects and continue to question the virus and the vaccine.

Swine flu was identified in Malta last June and since then vulnerable people with flu-like symptoms have been treated with the antiviral drug Tamiflu.

Two weeks ago the government moved towards the preventative vaccine and is hoping that by the end of March most of the public will be jabbed and the 425,000 doses ordered used up.

When the first batch of 100,000 doses arrived, the inoculation of the public started with health care workers followed by vulnerable groups. But who are these vulnerable groups and how are they determined?

"Determining who is vulnerable is assessed by clinical risk: if someone gets the flu, what are the chances of them developing complications? We know from experience that pregnant women, children and young adults - even more so if they suffer from chronic conditions - are more likely to develop complications if they get the flu," health care director general Ray Busuttil explained.

Morbid obesity

"The very fact you are overweight or obese will not be a detrimental factor for swine flu. You have to be morbidly obese for your weight to put you at risk in terms of this virus," Dr Busuttil said.

A person is considered to be morbidly obese when his body mass index - the calculation of weight in relation to height - is over 40. A person of normal weight would have a BMI ranging between 18 and 25.

Although recent research has shown that a fifth of the Maltese population is obese, very few are morbidly obese.

For this reason, health authorities did not list obesity as one of the risk factors, since obesity as such is not. "There was the risk that the word 'obesity' would confuse and alarm the public unnecessarily," he said.

Pregnant women

It is not clear why pregnant women have the highest risk factor of all groups. "We have instances where swine flu caused problems for healthy pregnant women and their babies. However, in terms of the vaccine, so far there have been no reports of negative effects on mothers or babies," Dr Busuttil said.

He recommended that pregnant women take the jab and explained that they would then pass on their antibodies to the baby in the womb or through breast feeding.

Unfortunately, he said, some pregnant women were concerned about long-term side-effects of the jab. "No one can give a guarantee there will be none, but that cannot be given for anything," he said, adding that the risks of contracting the flu outweighed those of taking the vaccine.

Young people and children

About two thirds of reported complications from swine flu cases were seen in people under 35. It is not yet clear why as this could be due to one of two factors: it could be an inherent property of the virus that it affects younger generations. However, this could be due to the fact that the older generation was exposed to a similar virus in the 1960s or 1970s and developed a resistance to it, Dr Busuttil said.

Vaccine controversy

Influenza vaccines have been around for many years and health authorities know how these behave and that they do not have long term side-effects, Dr Busuttil said.

In the case of the swine flu vaccine, a controversy erupted because of the way the vaccine was made.

In the case of the normal flu vaccine, each year pharmaceutical companies "cook the vaccine from the start" by mixing the target virus with a set of standard "ingredients".

The swine flu vaccine was not "cooked" from the start. "They pulled out the H5N1 (bird flu) virus and replaced it with H1N1 (swine flu)."

Dr Busuttil said people did not realise side-effects were produced by the "ingredients" and not the method used.

"The vaccine is safe. It is in nobody's interest to try to promote an unsafe vaccine. I don't think the World Health Organisation or health authorities of various countries would be stupid enough to push something that is not beneficial.

"The disease admittedly is, so far, mild but can become more aggressive. Despite the fact that it is mild it can still cause problems and kill healthy people. Although it is impossible to forecast any possible long-term side-effects, there is no doubt that the vaccine benefits outweigh the risks," he said.

How does the vaccine work?

The Maltese health authorities ordered 425,000 doses of the GlaxoSmithKline's H1N1 vaccine Pandremix. Patients are being asked to get jabbed, for free, at their local health centre.

The vaccine works by giving patients a small amount of killed H1N1 virus which will generate an immune response in the body that will start to create defences. In fact, people who have already had swine flu do not need to take the jab against the virus since they have developed their own defences.

The side-effects are caused by the virus itself that causes a reaction in the body resulting in aches and pains. The local redness on the injection site is usually a reaction to the other "ingredients".

The vaccine was originally licensed as a two-dose inoculation but research is showing that one dose is sufficient to give a good cover to most people under 60.

Maltese health authorities are starting by giving one dose to all to give "a fair cover" to everyone. "Once we get more doses we can start refining to make sure all have the maximum cover possible," he said.

Blood donations

The swine flu outbreak has not affected the number of blood donations made in 2009 compared to the previous year, according to the National Blood Transfusion Service head Alex Aquilina.

Approximately 50 blood donors turned up every day since the virus was detected, he said, adding that neither did the vaccine hinder people from donating blood.

People can donate a few days after being vaccinated so long as they do not have fever or suffer from aches and pains which may be side-effects of the vaccine, he said.

Dr Aquilina added that it was routine practice that people with flu-like symptoms were not allowed to donate blood and asked to return two weeks after the symptoms ended.

"There have been no cases of swine flu being transmitted through blood donation.... For us it is better that people get vaccinated. We could have problems with blood shortages if there was an epidemic and donors had not been vaccinated," he said.