New technology speeding up progress on bird flu vaccine
Faster DNA method shaved 2 weeks off vaccine process
Even as US officials this week awaited the arrival of a sample of the new bird flu virus from China - typically the first step in making a flu vaccine - government-backed researchers had already begun testing a “seed” strain of the virus made from the genetic code posted on the Internet.
This new, faster approach is the result of a collabouration among the US government, vaccine maker Novartis and a unit of the J. Craig Venter Institute, which is using synthetic biology - in which scientists take the genetic code of the virus and use it as a recipe to build the virus from scratch.
It was an idea born in the aftermath of the 2009 H1N1 pandemic, in which production delays and poor-quality seed strain slowed delivery of the vaccine until October, late enough that people were already sick with swine flu.
The new method has shaved two weeks off the vaccine-making process. It will take five to six months to ramp up production, but even weeks could make a difference in the case of a potentially deadly flu pandemic, said Robin Robinson, director of the Biomedical Advanced Research and Development Authority or BARDA.
“We’ll take it,” said Robinson, whose agency handles pandemic preparedness as part of the US Department of Health and Human Services. “If the virus turns out to be a tough one, that could be very important.”
At least 33 people have been infected and 10 have died from the strain of bird flu known as avian influenza A (H7N9) first found in humans last month. So far, the strain does not appear capable of being passed from person to person.
But Chinese researchers, in a report published online on Thursday in the New England Journal of Medicine, warned that the sudden emergence of this strain of flu “may pose a serious human health risk” and said “appropriate counter measures were urgently required.”
An especially deadly strain of bird flu in 2003 known as H5N1 had already raised the threat of a global pandemic, spurring more than US$2 billion in government contracts to shore up US flu vaccine manufacturing capabilities.
After the 2009 H1N1 pandemic, US health agencies gathered to do some soul searching. Representatives from BARDA, the Food and Drug Administration, the Centers for Disease Control and Prevention and the National Institutes of Health looked for ways to expedite the process of making flu vaccines, Robinson said.
These advances would need to apply to all vaccine makers, whether they used the traditional method of growing the virus in live chicken eggs, or the newer methods of growing it in cells or vaccines made from genetically engineered proteins.
Robinson, who formerly headed the vaccines division at Novavax Inc, had seen firsthand the speed at which a vaccine could be made using synthetic biology during the 2003 outbreak of Severe Acute Respiratory Syndrome or Sars, when companies and governments rushed to make a vaccine.
So, in 2010, BARDA tapped Novartis, one of its vaccine partners, along with a company owned by Dr. J. Craig Venter, the flamboyant scientist who took part in the race to map the human genome and caused a stir in 2010 when he used synthetic genes to create a custom microbe and bring it life.
As a test drive for the new flu technology, in 2011 the government gave its partners the genetic sequence for a North American strain of H7N9, a similar virus to the one making people sick in China. “It was just a coincidence,” Robinson recalls.
In less than two weeks, Novartis and Venter’s group were ready to make virus seed. The next year, they sequenced an H5N1 virus and produced a synthetic virus in six days.
Then came a live test. The United States asked its partners to make a real vaccine for a variant of swine flu known as H3N2 that had been infecting children in the US Midwest last year.
Once again, they produced virus seed in less than a week.
So, when Chinese health authorities released the genetic sequence for the H7N9 bird flu on March 30, US health officials decided to try the new technique.
Novartis and Venter’s company, Synthetic Genomics Vaccines Inc, went to work and by April 4, they had synthetic DNA ready and had started to grow the virus in cells, long before samples of the actual virus arrived from China on April 11.
Normally, getting a sample would be the starting point for making a seed virus, which would then be grown and tested to ensure it would grow well in chicken eggs or cells.
That involves a certain amount of guesswork, however. The new process of building the virus based on its genetic code allows “almost guaranteed success,” said Mike Shaw, director of the US Centers for Disease Control and Prevention.
“That is because you’re creating a virus that is almost tailor-made,” he said.
Shaw said the CDC plans to take a vaccine candidate at least to the stage of human safety trials, a process that will take several months.