Research released yesterday confirms public concerns about vaccine safety. Dr Muiris Houston, Medical Correspondent, looks at when and how the swine flu vaccine is likely to be administered and whether safety is a real or perceived issue
PANDEMIC (H1N1) 2009 influenza virus is now well established in the Republic. There is a steady flow of new cases each week, the majority experiencing a mild illness.
Of those who do require hospitalisation, at any one time between four and six patients need treatment in intensive care. But with autumn upon us and schools and colleges reopening next week, an increase in infection levels is likely.
The next major challenge facing both the health service and the healthcare industry is the production and administration of a pandemic vaccine. In effect, we face a race between the rate of vaccination and the rate of spread of the swine flu virus.
We know the Department of Health and the Health Service Executive (HSE) have contracts in place to provide us with 7.7 million doses over six to 12 months. The challenge is further complicated by the need to administer two separate doses of the pandemic vaccine. And all of this at a time when high- risk groups and those over 65 require a seasonal flu shot as well.
Both Baxter International and GSK are contracted to supply the Republic with pandemic vaccine. But even now, no one is absolutely certain when sufficient quantities will arrive to allow mass vaccination to begin. The HSE has confirmed that the first two groups to be offered the vaccine will be healthcare workers and people aged less than 65 who are considered at high risk of the H1N1 virus or its complications.
It is not yet clear whether vaccination will be confined to frontline healthcare workers, and T he Irish Timesunderstands that some tweaking of those considered at high risk may also take place.
But at some point we can expect to see both GPs and mass vaccination clinics offering the pandemic vaccine. The numbers involved are huge. About 10 per cent of the population have a chronic illness and the health service employs in excess of 100,000 people.
So the logistical challenges cannot be underestimated especially when each recipient must be vaccinated twice.
The HSE is unlikely to start vaccinating until it has at least two weeks of vaccine in stock. According to Dr Kevin Kelleher, assistant national director of population health with the HSE, the best estimate at this point is that vaccination is likely to begin in mid-October.
While the health service has not specified a minimum vaccine uptake target, in general terms a rate of more than 75 per cent is needed to achieve a herd effect. But there may be problems achieving this uptake level.
A survey of 1,500 nurses by the UK journal Nursing Times, most of whom were frontline practitioners, found that 30 per cent of respondents said they would refuse the swine flu vaccine. A further one-third said they were undecided about whether to get the jabs or not.
When asked why they were against vaccination, 60 per cent said they were concerned about the vaccine’s safety. A further 31 per cent said they did not consider the risks of swine flu to be great enough to warrant vaccination.
Vaccination rates for seasonal influenza among healthcare staff are disappointingly low, year on year. And apart from the risk to themselves, by not getting vaccinated nurses and others are exposing those they treat to additional risk.
Research published yesterday confirms the public’s safety concerns. Canadian researchers conducted a number of focus groups in Vancouver before the onset of the current pandemic and asked how willing they would be to accept a new vaccine in the event of a pandemic. Parents who favoured “alternative medicine” were especially opposed to vaccination.
"Participants were concerned that in a pandemic, a vaccine would be brought to market without sufficient testing for safety," the researchers said in the Emerging Health Threats Journal.
Meanwhile, US researchers last week challenged recommendations by the Centers of Disease Control for the prioritisation of swine flu vaccine. They suggested the optimal control of H1N1 spread would be achieved by prioritising vaccinations for schoolchildren and adults aged 30-39.
Others have pointed to 1976 when an outbreak of swine flu occurred in Fort Dix, a US army base. The strain appeared similar to the deadly 1918-1919 virus leading to a panicked political response by president Gerald Ford’s administration. He announced funding for a crash programme to manufacture enough vaccine to immunise “every man, woman and child” in the US.
However, in November 1979, reports began to emerge of a paralysing neurological illness called Guillain-Barré Syndrome (GBS) that seemed to be linked to the new vaccine. Subsequent analysis revealed an attributable risk of vaccine-related GBS of one case per 100,000 vaccines.
This proved to be a one-off occurrence; studies of large numbers of recipients since then have found an incidence of GBS following seasonal influenza to be about one per million vaccinations. Neurologists say the only people who need to avoid influenza immunisation are those with a personal history of the reversible neurological condition.
The principal common side effect of influenza vaccination is a mild soreness or swelling at the injection site, which usually clears up within two days. There is no reason why the pandemic H1N1 2009 vaccine should be any different.
Regulatory authorities, including the Irish Medicines Board and the European Medicines Agency, will make the final call on the safety of the new vaccine. While they will be under pressure to make a decision in less time than they are used to for the annual seasonal flu vaccine, an accelerated safety assessment combined with post-marketing surveillance should avoid any iatrogenic fall-out.
A pandemic vaccination programme is a massive public health challenge; with a modicum of luck it will go well and help prevent deaths and disability across the State.