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Quest for a vaccine against flu pandemic

— PHOTO: AP

MARIE-PAULE KIENY: Producing a pandemic vaccine is “a long journey.”

Two years ago, the Serum Institute of India based in Pune, the country’s largest vaccine manufacturer, joined an initiative launched by the World Health Organisation (WHO) to encourage six companies in developing countries to make influenza vaccines. At that time, the WHO was worried that the deadly H5N1 strain of bird flu might suddenly turn highly infectious in humans and send the virus rampaging across the globe.

Then, large quantities of a vaccine against such a pandemic flu strain would be needed as quickly as possible. Much of the world’s flu vaccine production capacity is currently concentrated in the industrialised nations. Besides, the richer countries are able to negotiate bulk contracts in advance with large manufacturers for pandemic vaccines.

But, now a flu strain known as Influenza A(H1N1) that originated in pigs is threatening a full-scale pandemic.

The Director-General of the WHO has already convened a meeting of all flu vaccine manufacturers, including those in developing countries, to discuss production of a pandemic vaccine against the H1N1 strain, said Marie-Paule Kieny, Director of WHO’s Initiative for Vaccine Research, at a press briefing recently.

The relative mildness of disease caused by the H1N1 strain outside of Mexico did not mean that a potential pandemic would remain mild. Preparations to make a pandemic vaccine against the H1N1 strain should proceed, she emphasised. “This is too much of a gamble over public health to say, ‘Well, let’s see if it really becomes severe.’”

Producing a pandemic vaccine is “a long journey,” remarked Dr. Kieny. From the time a potentially pandemic flu strain is identified, it takes between four and six months to have the first doses of the vaccine coming out of the factory. The best estimates currently available indicated that there would be a minimum of one to two billion doses of the vaccine available in one year, she added.

A recent study carried out by Oliver Wyman, an international strategy consulting firm, in collaboration with the WHO and the International Federation of Pharmaceutical Manufacturers & Associations (IFPMA), found that the capacity to make a pandemic flu vaccine had increased 300 per cent over the last two years. This would not be sufficient to meet global need for emergency production of a pandemic vaccine, said an IFPMA press release issued in February this year.

The IFPMA press release noted that the most likely case was of the manufacturers producing 2.5 billion doses of a pandemic vaccine in a year. At that rate, it would take four years to satisfy the global demand. But in the best case, if 7.7 billion doses could be produced in the first 12 months, global demand would be satisfied in one and a half years.

The WHO will approach the Serum Institute of India as also the other five vaccine manufacturers in developing countries to see if they could produce a pandemic vaccine against the current H1N1 strain, said Dr. Kieny. According to her, these six companies had received funding and technical assistance from the WHO to produce flu vaccines.

But in the case of the Serum Institute of India at least, they are not likely to be in a position to undertake bulk production of a vaccine in time to help with the pandemic that may be imminent. Their problems in doing so illustrate the difficulties in creating and maintaining the capability to meet sudden global demand for a vaccine that is needed for an emergency that occurs only once in several decades.

The six companies chosen by the WHO had first to demonstrate their ability to produce a seasonal flu vaccine, said Suresh Jadhav, executive director of the Serum Institute of India. If a company could not produce the seasonal flu vaccine, it would not have the infrastructure and the expertise to make pandemic vaccines. “It is like a proof-of-concept to show them that you can handle the seasonal [vaccine], therefore you will be in a position to handle the pandemic strain,” he told this correspondent.

The Serum Institute of India showed that it could produce the seasonal flu vaccine and was subsequently given the H5N1 bird flu seed virus to produce a pandemic vaccine. The H5N1 pandemic vaccine made by the company was now undergoing animal studies, according to Dr. Jadhav.

Now that the H1N1 strain, which might potentially produce a pandemic, had been isolated, the Centers for Disease Control in the U.S. as well as other WHO Collaborating Centres were "tweaking" the virus in order to create a seed strain that would then be shipped to vaccine manufacturers, said Dr. Kieny. This would be completed by mid- to end-May, she said.

The Serum Institute of India can then innoculate the seed strain of the H1N1 virus into fertilised hen’s eggs or animal cells that can be grown in culture. Although use of eggs is the time-honoured method for making flu vaccines and is still the dominant technique in terms of production volumes, cell culture processes are catching on.

The Serum Institute would use both egg and cell culture methods, said Dr. Jadhav. Cell culture simplifies the purification steps needed to make the final vaccine and also reduces waste disposal problems afterwards. Besides, cell lines can be scaled up more quickly than with eggs to meet larger production needs. Just to make 50,000 doses of a flu vaccine, some 15,000 to 25,000 eggs might be required. Properly handling so many eggs “really becomes a very tedious job,” he pointed out.

But the Serum Institute currently has facilities that can undertake only pilot scale production of flu vaccines. Full-scale production of flu vaccines required a new facility that is built to meet high bio-security standards, observed Dr. Jadhav. Such a facility could take two years to set up.

When would the company decide whether or not to put up such a plant? “Once we get proof of concept that ... this vaccine is feasible and what we have made has already given good results in animal studies and maybe in the Phase I studies in human beings for safety, that is the point when we will discuss with the WHO about their strategy,” he said.

Moreover, as a manufacturer, “there has to be a definite market, there has to be sustainability in somebody taking off your production,” he pointed out. So purchase contracts with the government and international agencies are needed.

Besides, there had to be a market even after the flu pandemic subsided. The WHO has been pushing very hard for all countries to start using seasonal flu vaccines, noted Dr. Jadhav. For flu vaccine manufacturers, it is then easy to switch from making seasonal flu vaccines to a pandemic vaccine.

For the present, in order to meet global needs if the current swine flu turns pandemic, the WHO was discussing with manufacturers the issue of access to a part of their production “for the benefit of the poorest people in developing countries,” said Dr. Kieny during her press briefing.

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