Sunday, July 26, 2009
As the race for a vaccine gathers pace, public health officials attempt to gauge the severity of the H1N1 flu virus, writes Susan Mitchell
In Ireland many of us will not receive the swine flu vaccine until 2010 -months after the flu season has begun.
For some that will simply be too late, but the delay is not for want of trying.
It has been predicted that between 20 and 40 per cent of the Irish population will contract the H1N1 pandemic strain, widely dubbed ‘swine flu’.
According to these figures from the European Centre for Disease Control (ECDC), that means at least one million of us will get the virus.
One in every 300 people reported to have had the virus in the US has died. In Britain, one in every 500 people reported to have been infected has died.
The word ‘reported’ is important here. Many more people have had H1N1 in the US and Britain and dismissed it as a common cold.
Therefore, public health specialists are reluctant to base the potential death toll in Ireland, or elsewhere for that matter, on those statistics.
That said, deaths are inevitable.
‘‘Even if you erred on the side of caution and estimated that one million people got it, and that one in every 1,000 of those people were to die, it is like four jets going down in Dublin airport,” said Professor Sam McConkey, head of the Department of International Health and Tropical Medicine at the Royal College of Surgeons in Ireland (RCSI).
The vaccine
Right now, the race is on to prepare a pandemic vaccine. That work began in earnest as soon as samples of the virus became available. The virus was grown using tissue culture, grown on living human cells. After that, scientists tried to identify where the virus originated and understand how it was spreading and mutating - a process known as sequencing.
McConkey said that the virus evolved all the time, but that health officials had to select what they believed was an appropriate strain in order to help find a vaccine. That was then used to create a seed vaccine strain which manufacturers have used.
Vaccines are made using fertilised eggs. To begin, scientists painstakingly inject a small amount of virus into each egg. That is grown, replicated and harvested in order to create large amounts of the virus needed to make a vaccine. This relatively crude process has remained broadly unchanged for 40 years.
‘‘It is a laborious and tedious process,” McConkey said.
What is H1N1?
‘‘The H1N1 pandemic strain is effectively a hodgepodge of different viruses,” he said. ‘‘We do not know how it formed.”
McConkey said the term ‘‘swine flu’’ was ‘‘misleading . . . as this is a human pathogen [agent that causes disease].The pigs are not the problem and it is not an agricultural problem,” he said.
Although a five-year-old boy in the small village of La Gloria, Mexico, is said to be ‘‘patient zero’’, with the earliest confirmed case of 2009 H1N1,no one knows exactly how he contracted the virus.
Vaccine makers have already reported problems; the amount of antigen, the active ingredient in a vaccine that is reaped from each batch of eggs, is only about 25 per cent to 50 per cent of the norm for seasonal flu vaccine.
As very few people have immunity to this flu strain, it has been anticipated that people will need two shots. This means that global production capacity would drop further.
The result is that it may be too late to vaccinate people against a first wave: vaccines could be applied only to protect against a second wave that often comes about half a year later.
This problem can be tackled, but not solved, using adjuvants - chemicals added to a vaccine that boost the immune system’s response. The US has never licensed an adjuvated flu vaccine, which could delay approval in America.
Europe does not face the same problem, but if the Obama administration demands pure vaccine from its suppliers, that would affect supply for the rest of the world. As of yet, the Obama administration has not confirmed what it plans to do.
Like all other health authorities, the Health Service Executive (HSE) has yet to receive a definitive time for delivery (see panel) of the vaccine. A HSE spokeswoman said frontline healthcare workers would be the first cohort of the population to receive the vaccine. People who are immuno-compromised and those working in essential services, such as the army and the gardai, will also be prioritised.
The spokeswoman said the HSE would give details of its vaccination plan when it received a time for delivery from manufacturers.
Mass vaccination programme
Running a mass vaccination programme is not without its difficulties. Dr Ronan Boland, chairman of the Irish Medical Organisation’s (IMO) GP Committee, said there were ‘‘enormous challenges in conducting a mass vaccination programme for Ireland and all other countries that have decided to do so’’. Boland said the average GP has between 1,600 and 1,800 patients.
‘‘Patients are going to need two doses one month apart. That means the average GP will have 3,500 vaccines to administer. Over a six month period that would work out at 30 a day,” he said.
‘‘The winter months are the busiest time for any GP. We will also be dealing with the clinical effects of the potential pandemic and significant absenteeism ourselves.”
Boland said the IMO’s GP Committee had indicated it was hugely supportive of the HSE’s efforts to date, but said it was his ‘‘personal view’’ that it would not be possible to deliver a mass vaccination programme solely through the country’s GPs.
‘‘We have asked the HSE to provide us with a concrete plan that is deliverable and to let us know what role they envision for GPs.”
Manufacturers’ fears
The world’s first human trials of the H1N1 vaccine began last week in Australia. Even as a new generation of vaccines is being developed, manufacturers are afraid of litigation for a product that cannot, for practical reasons, receive trials that would ordinarily be more extensive. GlaxoSmithKline has admitted that bringing the drug to market so quickly could affect quality.
‘‘While the vaccine still has to go through clinical trials, there will be a balance between how extensive they are and regulators feeling a need to speed up its availability. We might not have the luxury of time on our hands,” said Stephen Rea, a spokesman for GlaxoSmithKline.
Pharmaceutical companies also fear what they call a form of nationalism, whereby the small number of countries where manufacturing takes place - principally in Europe - might demand that their own populations are vaccinated first before permitting exports.
In a recent interview, World Health Organisation (WHO) director general Margaret Chan expressed huge concern over the fact that ‘‘most of the production capacity has already been booked up by wealthy countries. Again I have to ask the question: do the developing countries have to wait at the end of the queue?”
Another fear, which few have verbalised, is the possibility that H1N1 may mutate and prove resistant to any vaccine that is developed. ‘‘A genetic shift is possible, especially as the virus spreads out. If we were really unlucky that could happen,” said McConkey.
What can the public and business do?
The virus typically spreads from coughs and sneezes or by touching contaminated surfaces and then touching the nose or mouth. Symptoms are similar to those of seasonal flu, and may include fever, sneezes, sore throat, coughs, headache, and muscle or joint pains.
The public is being advised to take everyday actions to stay healthy. They include covering noses and mouths with tissues when you cough or sneeze; washing your hands often with soap and water, especially after you cough or sneeze; using alcohol-based hands cleaners; and avoiding touching your eyes, nose or mouth as that spreads germs. Most important, stay at home if you get sick, to avoid infecting others.
Businesses have been advised to hammer out a business continuity plan that would outline who would do what in order to mitigate high absenteeism rates. The HSE has advised businesses to prepare for absenteeism rates of around 15 per cent.
Among the challenges businesses may face, in addition to high rates of absenteeism, are disruption to supply chains and business travel, infection control among employees, drop in demand for goods and services, as well as strains on insurance and cashflow.
The HSE has advised businesses to prepare by appointing a pandemic coordinator and deputy who will understand the requirements, plan accordingly and communicate with staff in order to help protect staff and reduce the impact on productivity levels.
In the world of flu viruses, there are few rules, but public health officials have to try to gauge the severity and trajectory of theH1N1 flu virus in order to make complicated decisions regarding just how aggressively they should pursue other mitigation strategies, such as the closure of schools and airports.
They are watching the southern hemisphere, which is now going through its flu season, to try to determine whether the H1N1 virus will return in a more virulent second wave.
For now, it is awaiting game.
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