27th December 2009 LONDON — After a huge noise, speculations and concerns the CDC the Center for Disease Control & Prevention of USA has said H1N1 flu is far less dangerous than originally feared
Statesmanjournal.com has also reported quoting a British officials that H1N1 is about 100 times less lethal than the 1918 Spanish flu.
When the winter wave of H1N1 swine flu is over, it will have been no more severe than an average flu season, predicts Harvard researcher Marc Lipsitch, DPhil, and colleagues from the U.K. Medical Research Council and the CDC.
“The good news is that … the severity of the H1N1 flu may be less than initially feared,” Lipsitch says in a news release.
There are some big qualifications to that prediction:
Most of the deaths and hospitalizations in a typical flu season are elderly people. Most of those killed or hospitalized in the H1N1 swine flu pandemic are children and young adults.
Deaths attributed to seasonal flu include heart attacks, strokes, and other fatal conditions triggered by the flu. Nearly all deaths attributed to H1N1 flu are due to flu or to bacterial complications of flu.
The new predictions would be four or five times higher in populations without access to mechanical ventilation or intensive care.
The Lipsitch team now calculates that the H1N1 swine flu has a case/fatality ratio no higher than 0.048% — and maybe seven to nine times lower, depending on the methods used for calculation
To determine how deadly the virus is, the British health department tracked all reported H1N1, or swine, flu patients hospitalized between July and November. In a paper published online in the British journal BMJ, experts estimated that out of every 100,000 infected people in Britain, about 26 died.
That is about 100 times less deadly than the devastating 1918 Spanish flu, which killed at least 50 million people worldwide. Swine flu also appears to be nearly 10 times less fatal than the flu pandemics in 1957 and 1968, the British numbers showed.
Earlier this month, American researchers released a similar analysis of the virus that said H1N1 may turn out to be the mildest pandemic on record. The U.S. Centers for Disease Control and Prevention estimated swine flu has a lower death rate than seasonal flu.
The most recent CDC estimate, said swine flu has sickened nearly 50 million Americans and killed nearly 10,000.
For comparison, influenza and pneumonia were responsible for 56,326 deaths in the U.S. in 2006, which predates the current H1N1 outbreak, according to death and mortality data from the CDC.
However, the CDC also has reported that American Indians and Alaska Natives have died from swine flu at a rate four times greater than other Americans. American Indians and Alaska Natives have higher rates of diabetes, asthma and other conditions that make them more vulnerable.
British officials, meanwhile, said their swine flu cases fell by about half in mid-December, with an estimated 11,000 new cases.
When the World Health Organization declared swine flu to be a pandemic in June, it described it as “moderate.” Most people who catch swine flu have mild symptoms such as a fever or cough and recover without needing medical treatment.
A pandemic is a measure of how widely a virus spreads, not its severity. Because flu viruses evolve constantly, swine flu could mutate into a more dangerous form.
While cases appear to have peaked in several countries, including the U.S. and Britain, experts fear there could be another surge this winter.
In the BMJ analysis, British experts said about two thirds of patients who died in the U.K. had medical conditions that would have qualified them to get the swine flu vaccine when it was first available. The experts also said most people who died got Tamiflu too late, a finding they said justifies Britain’s policy of giving Tamiflu to everyone, including previously healthy people, who report swine flu symptoms.
That contradicts WHO advice, which recommends countries save Tamiflu for at-risk patients — such as pregnant women, the elderly, children and people with underlying medical problems. Other scientists have raised concerns about widespread Tamiflu use because the drug comes with side effects such as nausea, insomnia and nightmares.
Using Tamiflu liberally — as Britain does — may also encourage drug resistance. Despite having a fraction of the swine flu cases logged in the U.S., the number of viruses that appear to be resistant to Tamiflu found in both countries is nearly identical: 25 in Britain and 26 in the U.S.
Elsewhere, health officials in Vietnam have reported what appears to be the largest cluster yet of Tamiflu-resistant swine flu cases — seven people who traveled together on a long train ride.
In Britain, Tamiflu is largely dispensed by call center workers at a national swine flu hotline who have no medical training. WHO advises people to only take the drug on a doctor’s recommendation.