Robert Pogson

I am not expert in epidemiology but I know a thing or two about particles and data, so I will comment on the interesting influenza outbreak apparently focussed on Mexico.

Articles on the web give this information:

• the thing has been around Mexico for a few weeks
• 100+ people have died with related symptoms but only a few have lab tests proving the infection
• the infection shows DNA signs of connections with bird/swine/human influenza
• rate of death is from 2 to 14% depending on how many of the suspected cases are real infections with this previously unknown virus
• officials are not recommending travel bans because the virus has already spread around the world
• officials are recommending extra care in hygiene – tissues, handwashing and masks in some cases
• TamiFlu supposedly helps
• previous immunization against influenza may not help

So, what to make of this?

• travel to Mexico seems unwise
• while the apparent lethality of the virus is a concern, the slow rate of dispersal is encouraging – the hybrid nature of it must somehow be alerting our immune systems properly or the virus is more fragile than most, remaining functional a shorter time outside the body
• the risk of infection seems to be more serious where health-care is of a lower standard, most places on Earth
• travel bans would be in place if other countries were getting the death toll of Mexico
• the virus will be a plague on most of the world where people are crowded and have marginal or worse health-care systems

I hope I am wrong but continuing air travel will allow this thing to get out of control in more places. It could take months to develop a vaccine. Fortunately we are leaving the flu season in the northern hemisphere but the south is just entering that phase. South America and Africa have mixed health-care but Australia is pretty good. We shall see. Let us hope the virus does not mutate sufficiently to hit the bulk of the world’s population next year with no effective vaccine. Expect TamiFlu to max out capacity.

Some useful links:

• RSS Feed from CDC
• A Canadian page full of good information, I hope…

UPDATE:

New information shows a rapid increase in confirmed cases in the USA.

U.S. Human Cases of Swine Flu Infection
(As of April 28, 2009 11:00 AM ET)

State	# of laboratory confirmed cases
California	10 cases
Kansas	2 cases
New York City	45 cases
Ohio	1 case
Texas	6 cases
TOTAL COUNT	64 cases

We seem to be very close to escalating the threat level for a pandemic. We are at Level 4 but conditions seem right for Level 5 or 6:

“ Phase 5 is characterized by human-to-human spread of the virus into at least two countries in one WHO region. While most countries will not be affected at this stage, the declaration of Phase 5 is a strong signal that a pandemic is imminent and that the time to finalize the organization, communication, and implementation of the planned mitigation measures is short.

Phase 6, the pandemic phase, is characterized by community level outbreaks in at least one other country in a different WHO region in addition to the criteria defined in Phase 5. Designation of this phase will indicate that a global pandemic is under way.“