วันพฤหัสบดีที่ 7 พฤษภาคม พ.ศ. 2552

Swine flu


 Swine Flu Vaccine May Be Months Away 
                by Chananant Wongkunanant






The BBC news Health Reports that The quest for a swine flu vaccine

Wednesday, 29 April 2009 12:11 UK

The quest for a swine flu vaccine

By Clare Murphy 
BBC News health reporter

Vials containing samples of the swine flu virus are making their way from the US to a government laboratory north of London. The race for a vaccine is on.

Seasonal flu vaccine
Manufacturers are currently working on the seasonal flu vaccine

It is a global endeavour and will bring the public and the private together, but it could still take several months before a safe and effective jab is available.

Yet amid all this activity, the answer could in fact be right under our noses.

Tests are being carried out to establish whether the current seasonal flu vaccine could provide cross protection against what we are seeing at the moment, as there are similarities between the H1N1 human flu viruses and the new H1N1 swine flu.

If that were the case - and it's certainly not impossible - we would in the words of one virologist be "home and dry".

Been there before

Even if this does not confer protection, the picture does not appear to be a bleak one.

The spread of bird flu amongst humans several years ago sparked fears that a pandemic was imminent. Plans were developed, expertise harnessed and facilities built for mass production.

 If this had happened six years ago we would really be in a fix - we are in a better position than we have ever been in the history of this planet to combat this 
Professor John Oxford
Barts and the London School of Medicine

The vaccine industry has started to attract new investment and government subsidies after years of being a pharmaceutical backwater.

"It was a fantastic dry run," says Professor John Oxford of Barts and the London School of Medicine.

"If this had happened six years ago we would really be in a fix - we are in a better position than we have ever been in the history of this planet to combat this."

The World Health Organisation says it is already in touch with vaccine manufacturers - although is not at this stage putting in orders - but initial work is already underway in national laboratories.

The US Centers for Disease Control and Prevention, which is looking at the molecular properties of the virus and why it appears to have been more virulent in Mexico is hoping to have produced a "reference strain" to send to vaccine manufacturers around the second week of May.

The same process will take place in the UK, once the Health Protection Agency (HPA) receives samples of the virus at its laboratories in Potters Bar.

"We will take this virus apart and reassemble it with two genes from the swine virus and the genetic information code for a laboratory virus called PR8 which grows very well in hens' eggs and is safe for human infection," said Dr John Wood, from the HPA's National Institute of Biological Standards and Control.

"When we have recreated this new hybrid virus this will be grown in cells and hens' eggs ready to distribute to vaccine manufacturers."

This, he said, should be done within three to four weeks.

Kill not cure

But it may be at least four to five months before a vaccine is ready.

 Clearly, if you make a swine flu vaccine and the pandemic doesn't actually occur, we could end up with no seasonal flu vaccine 
Chris Viehbacher
Sanofi-Aventis

Safety is - unsurprisingly - paramount, as vaccines can often be worse than the disease they are trying to combat.

An outbreak of swine flu in 1976 infected 200 people in the US. Only one of them died, but a vaccine administered to 40m people killed 25 and led to 500 others developing Guillain-Barre syndrome, which can be fatal.

For those countries now entering the summer months with the flu season behind them, a delay in vaccine is not a real cause for concern. But in the southern hemisphere where countries are entering their winter months the picture would be different if the outbreak were to worsen.

One way of administering the vaccine could be by adding a swine flu component to the seasonal flu jab given out in the autumn.

But while production facilities are much more extensive than they once were, it could still take several years to produce enough swine vaccine to match global demand if the virus continues to spread and becomes more virulent.

And in the rush to combat swine flu - from which there have been fewer than 10 confirmed deaths - manufacturers still have to keep their eye on producing an effective vaccine for seasonal flu as they do every year.

In the US alone there are an estimated 25-50 million cases reported each year. These result in 150,000 hospitalisations and 30,000 to 40,000 deaths. Worldwide there may be as many as half a million deaths each year.

"Clearly, if you make a swine flu vaccine and the pandemic doesn't actually occur, we could end up with no seasonal flu vaccine," warned Chris Viehbacher, chief executive officer of Sanofi-Aventis.

In any event, swine flu appears to be responding well to anti-viral treatments like Tamiflu and Relenza. These drugs do not attack the virus itself but an enzyme that allows it to spread within the body. Taken promptly, they can reduce the severity and length of the illness.

But production of sufficient quantities - were they needed - could again be problematic, although pharmaceutical giants GlaxoSmithKline Plc and Roche Holding AG have both said they are stepping up production.




NYTimes.com explains Swine Flu Vaccine May Be Months Away, Experts Say

Swine Flu Vaccine May Be Months Away, Experts Say

Published: April 28, 2009

Federal officials said it would take until January, or late November at the earliest, to make enough vaccine to protect all Americans from a possible epidemic of swine flu.

Katie Orlinsky for The New York Times

Some companies like VaxInnate are trying to make flu vaccines from viral genes or proteins, without having to grow the viruses.

Readers' Comments

Readers shared their thoughts on this article.

And beyond the United States and a few other countries that also make vaccines, some experts said it could take years to produce enough swine flu vaccine to satisfy global demand.

Although production is much faster than would have been possible even a few years ago, it still may not be in time to avert death and illness if the virus starts spreading widely and becomes more virulent, some experts said.

In this country, the biggest problem is that despite years of effort, the country is still relying on half-century-old technology to make the flu vaccines.

Federal authorities have spent years and more than a billion dollars trying to shift vaccine production to a faster, more reliable method — one that involves growing the vaccine viruses in vats of cells rather than in hen’s eggs, the old technology. And there are numerous small companies developing totally new approaches that might allow for the production of huge volumes of vaccines in a matter of weeks.

But the cell-based production is not quite ready, and some of the newer techniques are not proven enough to satisfy many experts.

“Those are all great technologies, but it isn’t going to happen in time,” said Dr. Greg Poland, head of the vaccine research program at the Mayo Clinic.

Federal officials have not yet made a decision on whether the swine flu is enough of a threat to warrant vaccine production. But they are taking the initial steps.

A potential problem is that producing swine flu vaccine might interfere with production of the seasonal flu vaccinefor next winter.

“We would have to most likely make a compromise,” Andrin Oswald, chief executive of the vaccine division at the drug maker Novartis, said in an interview.

But Robin Robinson, who runs the emergency preparation research program for the federal Department of Health and Human Services, said most manufacturers would have finished producing the bulk of seasonal vaccine by June.

If production of the swine flu vaccine were to start right after that, the first 50 million to 80 million doses would be available by September, Dr. Robinson said.

A full 600 million doses, enough to provide the required two shots for each American, could be finished by January. If immune stimulants called adjuvants were added to the vaccine, that could reduce the dosage needed by each person, allowing enough doses to be ready by late November, he said.

The vaccine industry is in a much stronger position to respond now than it was five years ago, when the United States had only two flu vaccine suppliers and was hit by a severe shortage.

Now there are five suppliers to the domestic market. And the vaccine industry, once a backwater of the pharmaceutical industry, is attracting new investments, lured by government subsidies and higher prices for vaccines.

Still, a study done with the World Health Organization and the International Federation of Pharmaceutical Manufacturers and Associations estimated that it would probably take four years of production to satisfy fully global demand for a vaccine to protect against thebird flu strain that has concerned health authorities for the last few years.

Similar projections might apply to the swine flu vaccine, some experts say.

The bottom line is there won’t be enough vaccine quickly enough and the vaccine will largely go to the countries that already produce the vaccine,” because countries will restrict exports in a pandemic, said Dr. David Fedson, an independent expert on pandemic preparedness.

The federal government is encouraging manufacturers to set up production in the United States, since all companies but one, Sanofi-Aventis, now import their flu vaccines.

The government also gave $1.3 billion, spread among several manufacturers, to develop ways of producing the vaccine in vats of animal cells rather than in eggs. Cell culture is less vulnerable to contamination and the process could save at least a few weeks.

The results so far have been mixed. Solvay, which was awarded the biggest federal grant, nearly $300 million, decided it was economically too risky to build a flu vaccine plant in the United States. (Most of the grant money had not yet left federal coffers and will not be lost, Dr. Robinson said.) Sanofi-Aventis has also put cell culture production on the back burner, Dr. Robinson said.

But Novartis is building a cell culture flu vaccine factory in Holly Springs, N.C., which might be ready for use in 2010 or 2011. The federal government is providing nearly $500 million in construction costs and guaranteed vaccine purchases.





NYTimes.com explains Outbreak in Mexico May Be Smaller Than Feared

Outbreak in Mexico May Be Smaller Than Feared

Brennan Linsley/Associated Press

Workers at the Naval Hospital in Mexico City wore protective gear Friday in the area where people with possible flu symptoms were checking in.

Published: May 1, 2009

The swine flu outbreak in Mexico may be considerably smaller than originally feared, test results released there on Friday indicate.

Of 908 suspected cases that were tested, only 397 people turned out to have the virus, officially known asinfluenza A(H1N1), Mexican health officials reported at a news conference. Of those, 16 people have died.

Mexico had reported about 2,500 suspected cases as of Friday, but the number of real cases could turn out to be less than half the suspected number if further testing follows the same pattern as the original round. Officials said that the tests were being done quickly, and that 500 more would be completed Friday.

José Ángel Córdova, Mexico’s health minister, said, “This is a new epidemic, and we can’t predict exactly” what it will do. “We need more days to see how it behaves,” he said.

“Apparently the rate of infection is not as widespread as we might have thought,” he added. The materials needed for the test were provided to Mexico by the United StatesCenters for Disease Control and Prevention.

Officials at the centers declined to say what the new numbers might mean.

“We are continuously assessing new information, but it is still too early to draw conclusions about the extent of the spread of this new virus in Mexico or the severity of disease caused by it,” Dr. Nancy Cox, chief of the influenza section, said by e-mail, when asked to comment on the test results.

Dr. Javier Torres, the head of the infectious disease research unit at the Mexican Social Security Institute, Mexico’s main public health care system, said that he had been analyzing the past week’s influenza statistics.

“The number of those exposed and infected has gone up, and the number of fatal cases has gone down,” he said. “We can be comfortable with those facts.”

Officials at the World Health Organization, which has declared that a pandemic is imminent, declined to comment beyond saying that the investigation into the outbreak was continuing.

But a public health and infectious disease expert from Vanderbilt University, Dr. William Schaffner, said the test results were “going to change, I think in a substantial way, the image of this outbreak in Mexico.”

If the outbreak is much smaller than initially thought, Dr. Schaffner said, “It would, I think, enable the world’s public health community to take a deep breath and continue to track the outbreak and reduce the tendency, as the W.H.O. has been doing, to notch up on its pandemic scale.”

If the testing also shows that the disease has caused fewer deaths than the 170 or so suspected, Dr. Schaffner said, it might resolve a question that has been puzzling health experts since the outbreak began: why did the disease appear to be so much more severe in Mexico than in the United States? In the United States, cases have been mild and there has been only one death, that of a 23-month-old child from Mexico. Meanwhile, the disease continued to spread to other countries and was confirmed in more American states on Friday. The disease is expected to drop off during the summer, because flu viruses do not thrive in heat and humidity, but it could rebound in the fall and winter. The World Health Organization said that the flu vaccine given to millions of people for the most recent flu season appeared ineffective against the A(H1N1) strain, but that health officials were talking to manufacturers about creating a new swine-flu vaccine, which would take four to six months to produce.

Dr. Marie-Paule Kieny, director of the Initiative for Vaccine Research at the World Health Organization, said that unless the numbers of cases decreased significantly, “it seems mostly likely that the manufacturers will proceed and we will certainly support them.”

Officials at the Centers for Disease Control said a decision had not yet been made about whether to manufacture a vaccine, but President Obama said that the government would support it.

New cases were reported in Denmark, France, Russia, Hong Kong and South Korea on Friday, but they were not confirmed by the health organization. The United States reported 141 confirmed cases in 19 states, up from 109 cases in 11 states on Thursday.

Concerns about the disease are having an increasing impact. On Friday, a United Airlinesflight with 245 passengers heading from Munich to Dulles Airport in Washington landed in Boston instead because a female passenger had flu symptoms and the airline thought she needed prompt attention, a United Airlines spokesman said.

In New York, the school with the nation’s largest cluster of swine flu to date — St. Francis Preparatory School in Fresh Meadows, Queens — was set to reopen Monday after being closed for a week.

Researchers say that some genetic features of the virus may help explain why many cases tend to be mild.

“We do not see the markers for virulence that were seen in the 1918 virus,” said Dr. Cox, of the Centers for Disease Control. “However, we know there is a great deal we don’t understand about the virulence of 1918 or other viruses that have a more severe clinical picture in humans.”

It is too early to know what economic impact, if any, the flu outbreak might have on the United States economy. The Congressional Budget Office estimates that the recession will push this year’s national economic output 7.5 percent below its potential level. A true flu pandemic could shave off an additional 1 to 4.25 percent and could have a similar effect on the world’s output, too, some economists say.


      



My Reaction: 



1. First and foremost, with regard to the high number (50%) of infections that do not involve the swine flu virus, the W.H.O. needs to provide accurate information concerning the exact nature of the infection of half its suspected cases. This substantial number is not confirmed as infected with swine flu, which means that medical scientists have not yet gone to the bottom of these cases. As soon as confirmation is possible, it needs to be communicated to concerned citizens what exactly the cause of the infection is for half of 75 cases that show reactions similar to swine flu, but are actually not swine flu. Errors in scientific procedures are common but usually only in the range of 1-5%; in this instance ‘little more than half’ are suspected not to involve the virus. Such a discrepancy is too significant to ignore; this discrepancy could be the main reason why the rate of infection seems to vary considerably.




2. The past week’s influenza statistics throw up mixed results: an increase in the number of infections combined with a decrease in the number of fatalities is a hopeful sign even among pessimists. If the panic caused by the outbreak was over the top, then it can be concluded that this panic contributed to the containment of the spread. Unfortunately, we are nowhere near this conclusion as a mind-boggling question remains: why is there such a huge difference in the way the disease spreads in Mexico, and the way it does in the US? In Mexico the disease seems to be a lot more virulent than the same disease in the US. This is a major point that needs to be explained in order to be able to show the world that modern medical professional have a grip on this outbreak. Explanation of the facts is exactly what both affected and non-effected countries needs: not vague predictions.



3. Closer to home, and definitely more worrisome to Thais, is the first known case of infection in Hong Kong. The authorities’ reaction seemed very cautious as numerous police squads cordoned off the hotel where the first confirmed case of swine flu had stayed before he was quarantined in a hospital. This police action effectively quarantined up to 300 hotel guests and staff members. A further 50 people who where at the hotel at the time the infected man stayed, were being tracked in order to quarantine them as well. This might create a sense of fear mongering among residents. In contrast, it builds confidence that the authorities can contain the spread of the disease by using decisive measures.




4. Cross protection, meaning that one kind of vaccine formulated for one disease can also prevent another disease, is a major point being focused on. In the other word, the possibility of the current flu vaccine being effective in preventing the spread of the swine flu (for which no vaccine has been developed yet) is a hopeful factor in the bottle against swine flu virologists claim that this is a realistic approach to the problem, as it will still take several months before a safe and effective vaccine is produced against swine flu. All medical eyes are now on the tests being carried out to analyze the effectiveness of seasonal flu vaccine against swine flu. This would, if proven effective, make it relatively easy to combat swine flu as there are worldwide stocks of the seasonal flu vaccine. If the seasonal flu vaccine proves to be insufficient in its effect on preventing swine flu, then another solution would be to add a swine flu component to current stocks of the seasonal vaccine. The fact remains that it will take another 2-3 months to produce a specific swine flu vaccine, and another 2 years to produce enough supplies of this vaccine to inoculate the world’s population. The turning point will thus depend on whether the cross protection of the current flu virus is effective or not.





Conclusion: 

The solution to the swine flu problem could be nearer to us than we realize. The erratic characteristics of the disease point to a slower and less severe rate of infection outside Mexico. The currently being tested hypothesis of using the cross protection of the current seasonal flu virus as a tool to prevent the spread of swine flu. The upshot of these news articles is that there is a beaming light at the end of the tunnel: the swine flu disease will most probably not turn in to pandemic. 

  


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