16 January 2008

Pandemic preparedness in the 21st century


I'm back from another cerebral treat at the Swiss Re Centre for Global Dialog, Rueschlikon, Switzerland.



Andreas Reis, WHO Department of Ethics and Human Rights, reviewed the 50+ year history of pandemic preparedness. Back in 1952 the WHO created the Global Influenza Surveillance Network, now comprising 118 centres in 89 countries. Reis described how GISN has been tirelessly detecting and cataloging flu strains ever since.

The year 2000 saw the establishment of the Global Outbreak Alert Response Network (GOARN), which has already delivered vaccines and antivirals to more than 50 flu outbreaks in 40 countries.

GOARN has also advanced the thinking behind the institutional response to pandemics. Reis talked about the "Titanic" principle of vaccine allocation, in which women and children are privileged in the response to a pandemic.

He contrasted this with strategies in which health care professionals would instead get to jump to the front of the treatment queue. He emphasized that every strategy has its weakness.

Next came Basel county Chief Medical Officer Anne Witschi to describe the various phases of Switzerland's impressive outbreak response strategies. Witschi started with a description of Phase 3 of the response: the detection and isolation of a person infected with influenza A virus.

Contact tracing roots out those who have been exposed to the virus. Isolation of all traced contacts completes the picture for phase 4 of the response.

Phases 5 and 6 see mass vaccinations, - voluntary in Switzerland, and attempts to achieve social distancing. Social distancing refers to the prevention of any significant aggregation of people by shutting down schools, public transport and canceling all unnecessary workplace activity.

Remember that the Swiss government has stockpiled 8M doses of the antiviral Oseltamivir (Tamiflu) in anticipation of pandemic. Enough for every human in Switzerland.

Witschi described how Switzerland would manage the resulting traffic jams (no public transport) and boarder controls (people will make unpredictable moves to join family members and other loved ones). Much thought has gone into managing religious congregations.

Finally, medical insurance expert Peter Miller presented Swiss Re's models for predicting the death toll of a full blown pandemic. What was interesting for me was to learn that the mortality rate has never exceeded about 3% of those infected.

Miller was quick to point out how our preparedness has improved. A calamity of the scale of the 1918 Spanish Flu pandemic has, according to his models, been reduced to a 1 in 3000 year event.

One serious difference between the H5N1 flu virus and other threatening viral nasties is the time lag between when one can infect others and when symptoms start to show. Someone infected with SARS is symptomatic from the moment they can pass on the disease.

For H5N1, there is a 1 day time lag before the symptoms set in; a whole day when a victim can innocently infect others.

During question time marking the end of the meeting, the man sitting next to me raised his hand and asked Anne Witschi some probing questions about the Swiss stockpile of Tamiflu. "Is there really enough medical equipment to deliver treatment for everyone?", he asked.

"There's a full treatment course for every person in Switzerland," came the confident reply.

"And the syringes?" he probed. "Are there enough syringes stockpiled to keep treating people?".

Suddenly, just for a moment, the spell was broken. "There is still a small problem with the stock of syringes and needles," Witschi added sheepishly. The man ceased his questioning.

Afterwards, I asked the man whether he had already known the answer to his question. "I'm working in this area," he said. And then said no more.

Flu pandemics remain spooky, no matter how impressive 21st preparedness appears.