It’s been six months since the first cases of an unfamiliar respiratory illness were recognized, first in Mexico and then in the southwestern United States. We now know that those cases were the forerunners of H1N1 (swine) influenza, the first simultaneous global outbreak of a new flu strain in the 21st Century. The disease has spread fear and confusion, exposed the inadequacies of national and global pandemic preparations, and highlighted inequities in global sharing of resources.
H1N1 flu is a complex, difficult, fast-moving story. To help, here are some answers to questions about covering this and the next pandemic, along with a collection of resources assembled by Maryn McKenna, an independent journalist and author who participated in the EWC Health Journalism Fellowships. She specializes in infectious diseases and has been writing about pandemic flu since 1997.
I hear this flu called “influenza A/H1N1.” What does that mean?
There are three main types of influenza: A, B and C. A is the most common, causes the most serious disease, results in the largest epidemics, and has the most genetic variation. Influenza B and C infect only humans, but influenza A infects humans, animals (including pigs), and birds.
Science distinguishes among strains of influenza A by means of two proteins on the surface of the virus: hemagglutinin (which allows the virus to bind to cells and is designated H for short) and neuraminidase (which allows the reproduced virus to escape from cells and is designated N for short). To date, 16 Hs and 9 Ns have been recognized, meaning there are theoretically 144 influenza As, though not all have been observed in nature. Each of the H-N combinations is called a subtype.
Click here for a basic primer on flu viruses.
Flu occurs every year. Why is this flu so different?
Flu viruses change slowly from season to season via a process called “antigenic drift,” in which small mutations accumulate in successive generations of viruses. Those slight changes render the viruses different enough over months that a newly formulated vaccine is needed each season.
But flu can also change dramatically in a short period of time by a process called “antigenic shift,” which produces a new subtype. The sudden change from one subtype to another — for instance, from the H3N2 of seasonal flu to the H1N1 of this year’s new flu — is the hallmark of a pandemic.
Antigenic shift occurs:
- when several flu viruses infect a cell simultaneously and swap gene segments while reproducing, which may have given rise to this flu;
- when a flu virus jumps directly from an animal species to humans, as happened with the H5N1 avian flu in 1997 in Hong Kong;
- or when a flu virus that exists in animals slowly adapts to humans over years, which may have caused the 1918 “Spanish” influenza that killed an estimated 100 million people worldwide.
A primer on “antigenic shift” v. “antigenic drift” can be found here.
Why can’t we just give everyone a vaccine and short-circuit this pandemic?
Until the H5N1 avian flu began spreading from Southeast Asia in 2003, remarkably little attention had been paid to flu as a global health threat. As a result, much of the technology used to make flu vaccines has remained essentially unchanged for decades. It is a clumsy and time-consuming process that in most years has taken up to six months and uses specially raised fertilized chicken eggs. In an average year, that six-month timeline allows seasonal vaccine to be delivered just in time for flu season.
This pandemic has exposed the weaknesses of this production process, as explained here by Dr. Bruce Gellin, director of the National Vaccine Program Office in the U.S. Department of Health and Human Services.
(A faster process, called “cell culture,” has been approved by regulatory authorities in the European Union, but not in the United States. But even cell culture production cannot circumvent the surprise factor of a sudden subtype shift.)
In addition, because flu vaccine production has not been a high priority, given other global health issues such as the AIDS pandemic, the world’s manufacturing capacity for flu vaccine is far short of what would be needed in a pandemic. Most of that capacity resides in the industrialized world, leaving the developing world with its lesser infrastructure short of critically needed vaccine, as explained here.
As H1N1 proceeds, what key resources should journalists monitor?
For general knowledge:
- The Nieman Foundation at Harvard University’s extensive new resource for journalists, CoveringFlu.org.
- Influenza Report, a free online flu textbook.
- The medical journal Lancet’s H1N1 page.
- ProMED, the outbreak-alert mailing list of the International Society for Infectious Diseases.
- The Center for Infectious Disease Research and Policy, University of Minnesota.
For global spread and government actions:
- The World Health Organization’s H1N1 page.
- The WHO’s international lab network of Influenza Collaborating Centers.
- The U.S. Centers for Disease Control and Prevention (CDC)’s H1N1 page.
- The flu information page of the U.S. Department of Health and Human Services.
- The H1N1 page of the European Centre for Disease Prevention and Control.
- The Public Health Agency of Canada’s swine flu page.
- The Pan-American Health Organization’s H1N1 page.
- Developing world guidance produced by the International Federation of Red Cross and Red Crescent societies.
For vaccine information:
- The International Federation of Pharmaceutical Manufacturers and Associations flu vaccines page.
For aggregation and crowd-sourced reporting from around the world:
- The Flu Wiki.
- H5N1 blog (with many links to developing world blogs).
- Flu Trackers.
- Lancet H1N1.
- Effect Mediation blog.
_ by Maryn McKenna, independent journalist: public health, medicine, policy