China's swine flu shot heard round the world

When the news broke on August 19, international health officials, including Dr Anthony S. Fauci, head of NIH's National Institute for Allergy and Infectious Diseases, were understandably cautious. China's Sinovac Biotech company had not released data to support their claim that their swine flu vaccine required only one dose to be effective, which made it impossible to evaluate the claim.

But by then all eyes were turned to China. With the same showmanship that marked the opening of the 2008 Olympics, China's government had orchestrated a drama that was to unfold during a three-day international symposium on swine flu beginning August 21 in Beijing.

Virtually every vaccine expert outside China had predicted tests on human volunteers would show that two doses of swine flu vaccine were required. Yet China's swine flu vaccine trials, which were using 13,000 volunteers, dwarfed others underway around the world. If Sinovac's claim held up to scrutiny the ramifications could hardly be overstated. Details of the test results were to be unveiled at the symposium.

The confab, formally named the International Scientific Symposium on Influenza A/H1N1 Pandemic Response and Preparedness, hosted by China's Ministry of Health with the support of the World Health Organization (WHO) and the Lancet, had nearly 1,000 attendees from 30 countries and regions.

The attendees were heavy hitters in the public health and infectious disease management communities: top scientists, vaccine developers, health ministers and senior public health officials including those from the CDC and ECDC.

After interminable speeches and panel discussions, finally came the news everyone was waiting for. Bloomberg's Jason Gale reported on August 22 (Update 2 report; visit the Bloomberg site for several topic links in the report and the 3rd update):

A single standard dose of vaccine may be adequate to protect most people against swine flu, according to preliminary research in China that suggests twice as many people as projected could have access to the pandemic shot.

An experimental swine flu shot induced a protective immune response in 85 percent of adults who received an initial dose at the same strength used in a seasonal flu vaccine, Xiaofeng Liang, director of the national immunization program at the Chinese Center for Disease Control and Prevention, told a meeting in Beijing today.

Health officials are awaiting more data from China, as well as studies overseas, to confirm the results.

Authorities in the U.S. and U.K. have predicted two shots would probably be required, a regimen that would halve the amount of vaccine available to immunize people before the Northern winter.

“This is very promising information, and if we are able to get an immunogenic response with one dose as opposed to two doses, this would be a very significant change in our expectations,” Keiji Fukuda, the World Health Organization’s assistant director-general of health security and environment, told the meeting.

“Up until now, most of us have been thinking that two doses would be necessary to develop an immunogenic response.”

Interim Results

The results are based on interim results from two of the 10 [Chinese] companies conducting studies in China on vaccines to fight the new H1N1 virus. The first of the 13,000 test subjects to receive an experimental shot were vaccinated on July 22 and none had a serious adverse reaction to it, Liang said.

Several vaccine types and strengths are being tested in seven provinces of China across four age groups in studies supervised by the country’s CDC, he said.

The trials are assessing the safety and effectiveness of at least three different vaccine strengths in single or two-dose programs and involving inoculations based on whole and split viral particles, he said.

The studies also looked at whether an aluminum-based chemical called an adjuvant boosted the body’s ability to produce infection-fighting antibodies.

Vaccines produced annually for seasonal flu combine 15 micrograms of antigen -- the protein that prompts the production of antibodies -- to fight each of the three most common influenza strains.

Liang said that a similar dose would be needed to protect most people against the pandemic strain.

“Adolescents and adults had a better response than children and the elderly,” he said. “Taking into consideration the safety, immunogenicity and the cost, a 15-microgram, split vaccine without adjuvant could be used for future vaccination.”

The report's third update includes this paragraph:

No data is available in children younger than 3, Liang said. A final decision on whether one or two doses will be required to provide protection across all age groups in China won’t be taken until all the data has been collected and analyzed, he said.

If that sounds like a climbdown we'll have to wait and see.

It could be devastating for the vaccine manufacturers outside China, and a great embarrassment for governments who contracted with those companies, if they can't replicate the success of China's vaccine. In that event they could spend the next two months or maybe the rest of this century quibbling with China's test results.

So would Beijing decide it's the better part of valor, or at least the better part of doing business in today's complicated world, to go along with the crowd in the event the other vaccine trials showed the need for two doses?

I don't think so because there are too many lives at stake, too much threat from economic dislocation in the face of a pandemic, and a great many Chinese to vaccinate. From the discussion in the report, it's more likely they'll carefully match the number of shots to the requirements of different categories of people.

Even with the vaccine's success, China won't be able to roll out any more than 65 million doses by the end of this year. Yet that means they've been highly motivated to produce an effective one-dose swine flu vaccine without the added expense of an adjuvant's bells and whistles.

With China's quality control problems in mind -- toxic sidewall, lead paint on dolls, tainted milk product, etc. -- you might be tempted to ask whether getting immunized with China's swine flu vaccine would also mean you glow in the dark.

Well, if it's any comfort, China's Health Minister, Chen Zhu, got his first swine flu jab on July 22 and a second shot on August 22 and he hasn't dropped dead yet or turned green. But I doubt China's 2009 swine flu vaccine will be much available outside the country.

WHO has been so impressed with China's effort they've delivered the ultimate compliment: mooching. When WHO hits you up for freebies on behalf of the world's neediest that's a sign you've arrived as a pharmaceutical supplier.

As to how any WHO official would have the gall to ask a developing country with more than a billion people to share any of its small vaccine supply during a pandemic -- I hope Beijing tactfully interprets the touch as a request that their vaccine companies focus on making flu vaccines for the world's basket-case countries.

As for the purity of the vaccine, Beijing has a lot to prove because of the quality control issues and their crummy health system, which WHO politely refers to as "spotty."

At the start of this year Beijing made it a national goal to develop a world-class health system and get into pharmaceutical development and manufacturing in a big way. That's a part of their economic stimulus plan. They are now heavily invested, both emotionally and financially, in making the best flu vaccines possible.