Mexico swine flu 'a potential pandemic'

A new flu virus suspected of killing as many as 81 people in Mexico has the potential to become a pandemic, the World Health Organization's chief says.

Margaret Chan said the outbreak was a "health emergency of international concern" and must be closely monitored.

Health experts say tests so far seem to link the illnesses in Mexico with a swine flu virus in the southern US.

Several people have also fallen ill in the US, and the authorities there are watching the situation. A top US health official said the strain of swine flu had spread widely and could not be contained.

Speaking after a meeting of the WHO's emergency committee, Mrs Chan said that "the current events constitute a public health emergency of international concern".

The WHO is advising all member states to be vigilant for seasonally unusual flu or pneumonia-like symptoms among their populations - particularly among young healthy adults.

Officials said most of those killed so far in Mexico were young adults - rather than more vulnerable children and the elderly.

The committee has not recommended declaring an international public health emergency and raising the global pandemic alert level, a move that could lead to travel advisories, trade restrictions and border closures.

At least some of the cases show a new version of the H1N1 swine flu sub-strain - a respiratory disease which infects pigs but only sporadically infects humans.

H1N1 is the same strain that causes seasonal flu outbreaks in humans, but the newly-detected version contains genetic material from versions which usually affect pigs and birds.

The virus is spread through coughs and sneezes and through direct and indirect contact between people.

Mexican officials have confirmed 20 deaths from the virus and are investigating dozens more.

Schools, museums and libraries have been closed across the capital's region and people are being urged to avoid shaking hands or sharing crockery. Hundreds of public events have been suspended and schools in the Mexico City area have been closed until 6 May. Two previously sold-out soccer matches were played in empty stadiums to avoid potentially spreading the virus.

Health officials are isolating individuals suspected of having the virus and inspecting their homes.

The Roman Catholic Church in Mexico has recommended measures to avoid further contagion at Mass this Sunday.

Priests have been told to place communion wafers in the hands of worshippers rather than in their mouths and to suggest to the congregation that kissing or shaking hands be avoided during the service.

In the US, 11 people are now known to have been infected with the new strain - seven people in California, two in Texas, and two in Kansas. There are also eight suspected cases in New York City after 200 students at a high school fell ill.

Specimens were taken from nine students, and eight were determined to be probable cases of swine flu, said city health commissioner Dr Thomas Frieden. Those samples are now being examined by the US Centers for Disease Control and Prevention (CDC).

No children had required hospital treatment and many had fully recovered, said Dr Frieden, but the school could remain closed out of "an abundance of caution".

He urged people to maintain basic hygiene, such and covering their mouths when coughing and sneezing, washing hands regularly and keeping surfaces clean.

Dr Frieden said most people would not need to take antiviral medication if they fell ill, unless they had an underlying medical condition.

CDC officials have said that with cases arising in so many communities, containment is unlikely to be feasible.

There is currently no vaccine for the new strain.

Tom Skinner of the CDC told the BBC that it was too early too tell how widespread the impact would be.

"We don't know how well or efficiently this virus is spreading and how easily it is going to be sustained in the human population."

He said it was not yet clear which side of the border the virus had originated.

But the US was likely to take "normal and routine" steps within the next few days to screen passengers coming into the US and to distribute information, he said.

The CDC plans to send experts to Mexico to help investigate the virus which has infected more than 1,000 people in the country.

The BBC science editor Susan Watts says the new strain is a classic "re-assortment" - a combination feared most by those watching for the flu pandemic.

Two Questions To Ask About Bird Flu Vaccines

by John Hart

The results of a government-funded study show that very high doses of an avian influenza vaccine, supplied by Sanofi-Aventis, are needed to produce an immune response that should guard against the virus. 54% of the volunteers received two shots of 90 micrograms each, 28 days apart. A typical flu shot is 15 micrograms.

Based on the requirements seen in the study, the U.S. government's current stockpile of vaccines would provide enough for only about four million people, according to Dr. Anthony Fauci, director of the National Institute of Allergy & Infectious Diseases.

The problem isn't just a matter of dosage. It is also a matter of production. Flu vaccines are produced using hen's eggs,a 50-year old technology, if it can be called that. Automated machines inject hundreds of thousands of eggs, then an 11-day waiting period begins while the eggs incubate, brewing viruses that are then killed and bottled. To produce millions of the the final product takes about six months.

Then there's the question no one seems to be asking: if we plan to rely upon chicken eggs to incubate an H5N1 virus, how do we know the H5N1 virus won't kill the eggs? H5N1 already kills chickens. Shouldn't we assume it also kills a high percentage of chicken eggs? Sanofi-Aventis is spending $150 million of its own money building a new vaccine-making plant based on the theory that H5N1 won't kill the eggs. By the way, eggs have to be ordered many months in advance for this antiquated process.

And where does Sanofi-Aventis plan to get all these egg-laying chickens anyway? Millions of chickens have been slaughtered worldwide already and a pre-pandemic scenario could kill off whole U.S. chicken farms at once.

However, there is a new vaccine technology on the horizon. It's called cell-based vaccine. Giant vats of living cells, such as dog kidney cells, multiply and then are inoculated with the virus. There are two companies already in the marketplace, one in Holland, one in Germany, but the technology won't be widely available for years. The FDA must review the entire method before any equipment can be imported to the U.S.

Clearly, the U.S. has waited for a new virus to come along to spur vaccine research. We may have waited too long. H5N1 isn't waiting. It's figuring out how to mutate into human-to-human transmission. In fact, the rate of mutation is alarming. Dr. Robert Webster, Ph.D., Member, St. Jude Faculty Rose Marie Thomas Chair, calls H5N1 "the most frightening virus I've ever seen in 40 years of research."

If you and your family are counting on a vaccine to protect you against H5N1 (Avian Influenza), don't bet on it. There are still too many unanswered questions and too many risks.

About John Hart
Mr. Hart is a medical journalist/researcher, and the author of "Killer Bird Flu...Get Ready Now!" a paperback that outlines what families can do to get prepared for the coming pandemic. Learn more at http://www.buynanomask.com.