Swine Pearls

The Spanish flu pandemic of 1918 resulted from a subtype of avian influenza strain H1N1. It killed anywhere from 50 million to 100 million people--3% to 6% of those then on earth. So while 2009's H1N1 "swine flu" pandemic wasn't exactly the same thing--it came from a new strain created when a previous triple reassortment of bird, swine and human flu viruses combined with a Eurasian pig flu virus--it made sense to take it very seriously.

Israeli health officials had just dealt with an outbreak of highly pathogenic avian influenza (H5N1) in 2006, and that yielded some lessons. The outbreak that year was detected more or less simultaneously in Israel and the Palestinian-controlled Gaza Strip. Control measures included culling of poultry and destruction of poultry products (farmers were compensated for their losses, which encouraged them to cooperate), identifying human cases and giving prophylactic Oseltamivir to humans who contacted poultry. Israeli officials worked cooperatively with Palestinian officials, and the measures helped control the outbreak in less than three weeks without use of vaccines.

The 2009 outbreak started in Mexico in March, and by April cases cropped up in the U.S. and Israel. Israeli officials responded with containment efforts: Suspected cases were initially hospitalized pending confirmation with lab diagnosis, contacts were voluntarily quarantined, and a clinic was set up at Tel Aviv's Ben Gurion Airport to intercept and screen travelers from Mexico. By June officials decided there was no reason to hospitalize every case. As the patient volume increased and health leaders around the globe got a better sense of what they were dealing with, they also stopped doing lab diagnoses for all.

By August the response shifted into treatment and modeling phases. Vaccinations started in October and lasted into 2010. Priority was given to high-risk patients, pregnant women and healthcare workers. Then the last year to year and a half has focused on distilling lessons and improving plans for next time. Lessons include:

• Keep policy dynamic and update it with circumstances. As a review of the 2006 response concluded, "Case definition and antiviral prophylactic policies may be revised ad hoc according to the unfolding events and in response to the medical and psychological needs of each population."
• Media coverage influences public perception. In Israel, surveys found 69% of respondents willing to get the H1N1 vaccine in August 2009, but by October, as people came to believe the pandemic wasn't that bad, that number dropped to 43%.
• Strengthen public health personnel and infrastructure (laboratory capacity, etc.). Personal hygiene should be a permanent measure, not temporary.
• Expand the decision-making circle as needed.

Vaccine Concerns

One of the challenges of the 2009 response was that the H1N1 strain was new, and no one was quite certain how deadly it might turn out to be, how fast it might spread or how it might mutate. There were concerns about vaccine availability and safety, as well as whom to target.

Ultimately the swine flu of '09 wasn't as severe as feared. Around 18,000 global deaths have been attributed to it, though that's almost certainly undercounted, and additional waves may still recur. In Israel, 70% of its deaths were limited to those with major risk factors.

The steps credited by Israeli officials for stemming H1N1 in that country fit a profile comparable to what we saw in America: good surveillance and early detection; primary containment measures; a focus on hygiene; use of antivirals; and intensive treatment of the severely ill. There as here, though, vaccinations proved a surprisingly hard sell. Just 9% of the Israeli population was ultimately vaccinated, and around 30% of healthcare workers. The U.S. actually did better: Per the CDC, those numbers here were 13%–39% of the public and 37% of healthcare personnel.

The U.S. Perspective