The good news is that the number of new cases appears to be dropping off in most of the United States. More good news is that the swine flu vaccine appears to be reasonably safe, with no increases in serious events, including death, above the expected baseline rate. The not-so-good news is that a currently noted "peak," in flu language, is temporary. Additional waves of increasing illness are expected. The other bad news is that pediatric deaths from the swine flu are already considerably higher than in past seasonal flues, and the numbers are expected to continue rising.
Update from the CDC, Weekly 2009 H1N1 Flu Media Briefing, Anne Schuchat, director of vaccination and respiratory disease at the C.D.C:
these estimates will give a single number and then a range, a lower and upper estimate around each number…. So for April through October 17th, we estimate the 22 million people have become ill from pandemic influenza. We estimate 98,000 people have been hospitalized so far through October 17th. And the upper and lower estimates on hospitalizations are from 63,000 to 153,000. We estimate that 3,900 people have died so far in the first six months of the pandemic from this virus. And the estimates there are from 2,500 up through 6,100 people having died so far. We’ve been talking a lot about this pandemic being a younger person’s disease, that it’s disproportionately affecting children and young adults and relatively sparing the elderly, very different from seasonal flu… [In] children under 18, we estimate 8 million children have been ill with influenza, 36,000 hospitalized, and 540 children have died…
I do believe that the pediatric death toll from this pandemic will be extensive and much greater than what we see with seasonal flu…The numbers I’m giving are through the first six months through October. We have had a lot of disease since then and we’ll probably have a lot of disease going forward…
What does this look like compared to previous pandemics. The estimates I’m giving you are the first six months. This is April through the middle of October. We have a long flu season ahead of us. In typical seasonal flu we see disease from December to May, it’s only November. So exactly what we will see as a full toll of illness from this pandemic is very difficult to say. I can say, though, that what we’re seeing with this h1n1 virus is nowhere near the severity of the 1918 pandemic. That caused much larger numbers six months in…
Number of cases declining in U.S.
The New York Times reports that according to the American College Health Association, "new cases of flu among college students have started to drop, hinting that this wave of the swine flu pandemic has peaked… The association does weekly surveys of more than 250 colleges and universities with a total of three million students, and new cases of flu in the week that ended on Friday dropped by 27 percent from the previous week. About 80,000 of the students have had flu symptoms, about 150 have been hospitalized and last week there were two deaths." According to the LA Times only 3% of college students have been vaccinated.
The current wave of swine flu seems to have peaked in the U.S. However, Dr. Schuchat warns that "peaking" does not mean the flu is going away. Further waves of infection are typical of flu viruses. The spread of disease is also increasing in some regions, such as Hawaii, Maine, Canada, Norway, and Eastern Europe, and Central Asia. Signs That Swine Flu Wave Has Peaked in U.S., Centers for Disease Control and Prevention.
Moreover, even if new infections decline, that will not instantly be reflected in hospitalization and deaths. (But see H1N1 deaths, hospitalizations slow in California.) Dr. Lone Simonsen, a former C.D.C. epidemiologist, expects a third wave of infections in December or January. And according to Anne Schuchat, more H1N1 flu is circulating now compared to the height of usual flu seasons. "It is so early in the year to have this much disease. We don’t know if these declines will persist, what the slope will be, whether we’ll have a long decline or it will start to go up again." Swine Flu Seen as Cresting (WSJ).
A mutation, called the D222G mutation has been found in three people in Norway. The D222G mutation is on the receptor binding domain, and it allows the virus to penetrate further into the lungs. According to Geir Stene-Larsen, director of the Norwegian Institute of Public Health, only three of Norway’s 70 tested samples had the mutation and it did not appear to be circulating. Rather, this mutation appears to arise in cases spontaneously. NY Times, Signs That Swine Flu Has Peaked:
Asked about that, Dr. Schuchat said the same mutation had also been found in mild cases in several countries, and it did not make the virus resistant to vaccine or to treatment with drugs like Tamiflu. She said she did not want to “underplay” it, adding that “it’s too soon to say what this will mean long term.”
The D222G mutation allows the virus to bind to receptors on cells lining the lungs, which are slightly different from those in the nose and throat. Henry L. Niman, a flu tracker in Pittsburgh, has been warning for a week that D225G — the same mutation under a different numbering system — has been repeatedly found in Ukraine, which is in the grips of a severe outbreak and where surprising numbers of people have died with lung hemorrhages — the kind of pneumonia that can be caused by an immune system’s “cytokine storm” attacking a new virus.
According to the Washington Post, Norwegian scientists detect mutated form of swine flu,
“the Norwegian Institute of Public Health said the mutation “could possibly make the virus more prone to infect deeper in the airways and thus cause more severe disease,” and that ”there was no indication that the mutation would hinder the ability of the vaccine to protect people from becoming infected”…
The World Health Organization said viruses with a similar mutation had been detected in several other countries, including Brazil, China, Japan, Mexico, Ukraine and the United States. “No links between the small number of patients infected with the mutated virus have been found and the mutation does not appear to spread,”…
Several flu experts said that the mutation should not cause widespread alarm. “Influenza is a mutable virus, and changes are to be expected,” said Arnold S. Monto of the University of Michigan in an e-mail. “This is typical early in the spread of a pandemic virus.”
The Norway mutation may cause more severe disease by infecting deeper into the respiratory track. However, viruses from numerous fatal cases have not shown this mutation and the significance of the Norway mutation needs to be further investigated. (Washington Post, WHO says swine flu samples from Ukraine showed no significant mutation, WHO investigating Norway swine flu mutations.)
Other mutations have also been found. Bloomberg reported that "five patients at a hospital in Wales contracted swine flu that resisted treatment with Roche Holding AG’s Tamiflu, and three more infections are being analyzed… Four patients had resistance in a North Carolina hospital." This mutation may have spread to other patients. "The infections in Wales may have passed from a person using Tamiflu to patients who haven’t taken the drug, raising the possibility that a hard-to-treat form of the disease may spread,…" Mutated Swine Flu Strains Block Drugs, Worsen Illness.
Vaccine – evidence of safety
The World Health Organization reported that among the 65 million adults and children who received a swine flu vaccine since September, less than 30 died and less than 10 developed Guillain-Barre Syndrome. None of the deaths appeared to be associated with the vaccine. The findings so far indicate that the swine flu vaccine has a negligible risk for causing serious side effects, such as Guillain-Barre syndrome, and death. See Safety of pandemic vaccines, Pandemic (H1N1) 2009 briefing note 16:
19 NOVEMBER 2009 | GENEVA — To date, WHO has received vaccination information from 16 of around 40 countries conducting national H1N1 pandemic vaccine campaigns. Based on information in these 16 countries, WHO estimates that around 80 million doses of pandemic vaccine have been distributed and around 65 million people have been vaccinated. National immunization campaigns began in Australia and the People’s Republic of China in late September.
Vaccination campaigns currently under way to protect populations from pandemic influenza are among the largest in the history of several countries, and numbers are growing daily. Given this scale of vaccine administration, at least some rare adverse reactions, not detectable during even large clinical trials, could occur, underscoring the need for rigorous monitoring of safety. Results to date are encouraging…
To date, fewer than ten suspected cases of Guillain-Barre syndrome have been reported in people who have received vaccine. These numbers are in line with normal background rates of this illness, as reported in a recent study…
A small number of deaths have occurred in people who have been vaccinated. All such deaths, reported to WHO, have been promptly investigated. Although some investigations are ongoing, results of completed investigations reported to WHO have ruled out a direct link to pandemic vaccine as the cause of death…
Previously, I suggested that the seasonal flu vaccine confers some protection against the swine flu. There have been studies showing a protective effect, studies showing no effect and one study suggesting an increase in risk. Weekly 2009 H1N1 Flu Media Briefing, Anne Schuchat.
Great panic ensued after 16 swine flu deaths occurred in a single day in Ukraine. This caused many scientists to wonder if the virus had mutated from its original form or was more similar to the Spanish Flu than Swine Flu.
However, after analyzing 34 samples, it is clear that the Ukraine swine flu deaths were just that: deaths due to H1N1, not a mutated version of the virus.
The Ukraine virus, which is similar to the swine flu, according to the World Health Organization, has now claimed the lives of 354 people since the beginning of October. According to recent reports, the Ukraine government intends to lift the quarantines and other protective measures put in place to protect against the spread of the Ukraine flu… Government officials have stated that the situation has stabilized, and quarantines are no longer necessary. In addition, there may be some concern of quarantines interfering with the upcoming presidential elections.
In summary, the swine flu vaccine appears to be safe, the infection rates in most of the U.S. appear to be dropping off (though expected to resume), and the significance of the Norway mutation is unknown. Investigations of the Norway mutation, as well as mutations leading to Tamiflu resistance, are ongoing.