Potential Peak In US Swine Flu Cases
Officials with the U.S. Centers for Disease Control and Prevention said Friday that the swine flu pandemic might be reaching its peak in the U.S., although the outbreak could hit several such peaks within a single season.
"We are beginning to see some declines in flu activity around the country but there is still a lot of influenza," said the CDC’s Dr. Anne Schuchat during a news conference.
"It is still much greater than we would normally see this time of year,” she said, adding that weeks or months more of swine flu infections could be expected.
"There can be multiple ups and downs over the season. We have many weeks ahead of us where disease is going to be circulating.”
Separately, a team at Quest Diagnostics analyzed 142,000 flu tests and detected a similar pattern, with tests indicating a decline in illnesses since October 27.
"The number of specimens that tested positive for 2009 H1N1 influenza dropped in all age groups since late October, with the exception of those 65 years of age and older," said the company in a statement.
"Our data provides encouraging signs that the 2009 H1N1 pandemic virus isn’t spreading as aggressively now as it did in September and most of October," said Quest’s Dr. Jay Lieberman.
"This is encouraging but it doesn’t mean that they still shouldn’t be concerned about influenza. It’s not over," Dr. Lieberman told Reuters.
The U.S. holiday travel season will soon be underway, with millions traveling during the week of Thanksgiving and over the December holidays.
"Some people say, well, all the kids get together with their grandparents and that’s a lot of exchange of warmth and love, but a little exchange of viruses, too," Dr. Schuchat said.
At least 22 million Americans have been infected with H1N1, with 3,900 deaths, according to data from the CDC, with 21 U.S. children having died from H1N1 during the past week.
The figures bring the total of confirmed pediatric deaths from swine flu to 171, with estimates that more than 500 children have died since April.
The U.N. World Health Organization (WHO) said Friday that some 6,750 people have died worldwide from the swine flu pandemic since April — about 500 more than a week ago.
The death toll remains the highest in the Americas, where 4,806 deaths have been recorded, the WHO said.
The Asia-Pacific region reported 1,323 deaths, while in Europe, at least 350 people have died. Sri Lanka, Pakistan and Slovenia have each posted their first deaths from the swine flu virus.
VACCINE SHORTAGES
The CDC is still struggling to get enough vaccines, Dr. Schuchat said, with more than 54 million doses having been ordered so far.
Although the agency had originally intended to have 20 million doses per week available by now, just 11 million doses have been made, packaged and shipped during the past week.
The shortfall has some U.S. health officials looking regretfully at one easy way to have instantly doubled or tripled the number of available doses ““ the use of an immune booster known as an adjuvant.
These additives broaden the body’s response to a vaccine, reducing the amount of active ingredient called antigen required.
Adjuvants are widely used in flu vaccines in Europe and Canada, but not in the United States — despite the federal government having spent nearly $700 million purchasing them.
The reason is that some people do not trust them.
"If we really do want pregnant women to trust this vaccine or even parents, we have to think about what is acceptable to them," Dr. Schuchat said in an interview with Reuters.
"We have so much vaccine hesitancy in this country," said Jeff Levi of the non-profit Trust For America’s Health.
"To add … a new element could well have undermined the efficacy of this campaign," Levi told a Congressional subcommittee hearing this week.
This is frustrating for the WHO, which argues that the global capacity to produce about 3 billion annual doses of flu vaccines is inadequate to protect a global population of 6.8 billion people.
The WHO is hoping that wealthy nations will donate any leftover swine flu vaccine to others.
The U.S. Health and Human Services Department was prepared to try adjuvants in the event the swine flu pandemic had worsened.
"If things had been worse and this would have been a more severe pandemic, we may well have needed to go that way anyway," Levi said.
Instead, the U.S. has kept to what CDC director Dr. Thomas Frieden calls the same "tried and true" approach used in seasonal flu vaccines made by Sanofi-Aventis, CSL, Novartis, AstraZeneca unit MedImmune and GlaxoSmithKline.
The companies had urged Congress earlier this week to help federal agencies approve the use of adjuvants, and to assure skeptical citizens about their safety.
Recent polls show that just fifty percent of Americans plan to be vaccinated against H1N1. Of those who do not, roughly half cited safety concerns.
Dr. Vas Narasimhan, president of Novartis Vaccines USA, emphasized that adjuvants had been licensed for use in Europe for a decade and tested in some 200,000 people.
"Adjuvanted vaccines produce higher immune response than unadjuvanted vaccines particularly in the elderly and young children," Dr. Narasimhan said during the Congressional hearing.
They may even protect better than standard vaccines against viruses that have drifted, he said.Â
This drift is the primary reason that flu vaccines have to be re-formulated each year.
The adjuvants may even help require less vaccination.
"Adjuvanted vaccines have been shown to more broadly prime patients’ immune response (up to seven years later), requiring fewer vaccinations to the newly circulating strain," he said.
RESISTANT STRAINS
During the CDC’s press briefing, officials said they were looking into four cases of H1N1 resistant to Tamiflu at Duke University hospital in North Carolina.
"All four patients were very ill with underlying severely compromised immune systems and multiple other complex medical conditions," said Duke University said in a statement.
Health experts in Britain are also investigating a similar occurrence of Tamiflu resistance among seriously ill patients.
And experts are also watching out for any indication of widespread drug-resistance of the H1N1 virus.
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Last year, the seasonal version of H1N1, a distant cousin of the pandemic strain, developed resistance to Tamiflu, although GlaxoSmithKline’s rival inhaled drug Relenza was still effective in treating infections.
On Friday, the WHO said that a mutation had been identified in samples of the swine flu virus obtained after the first two swine flu deaths in Norway.
"The Norwegian Institute of Public Health has informed WHO of a mutation detected in three H1N1 viruses," said the WHO in a briefing note.
"The viruses were isolated from the first two fatal cases of pandemic influenza in the country and one patient with severe illness," the WHO said, adding that no further instances were found in tests.
"Norwegian scientists have analyzed samples from more than 70 patients with clinical illness and no further instances of this mutation have been detected. This finding suggests that the mutation is not widespread in the country.”
A similar mutation had been seen in Brazil, Japan, Mexico, China, Ukraine, and the U.S., as early as April, the WHO said.
"The mutations appear to occur sporadically and spontaneously. To date, no links between the small number of patients infected with the mutated virus have been found and the mutation does not appear to spread.”
The WHO emphasized that there was no evidence of additional infections or more deaths as a result, while the mutated virus remained sensitive to antiviral drugs used to treat severe flu, Tamiflu and Relenza.
"Studies show that currently available pandemic vaccines confer protection," the U.N. health agency said.
Scientists worry that any mutations in the flu virus could cause a more virulent and lethal pandemic flu. Â
The WHO is still reviewing the significance of the latest findings, but noted that many such changes in the virus do not alter the illness it causes in patients.
"Although further investigation is under way, no evidence currently suggests that these mutations are leading to an unusual increase in the number of H1N1 infections or a greater number of severe or fatal cases," it said.
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