ScienceInsider

by Jon Cohen

As public health officials have stressed since the swine flu pandemic surfaced last April, influenza is unpredictable. But one thing is predictable: pandemic influenza viruses come in waves that typically peak about 6 to 7 weeks after they begin to climb. New data from the United States and the United Kingdom hint that the second wave of the swine flu pandemic may have peaked in these countries.

According to a situation update released by the U.S. Centers for Disease Control and Prevention today, widespread disease last week dropped from 48 states to 46. That may not seem like much, but visits to the doctor for influenza-like illness also declined for the second week in a row after 4 weeks of “sharp” increases. CDC divides the country into 10 regions, and this drop in doctor visits was seen in all but one of them.

by Jon Cohen and Martin Enserink

First the bad news: Revised estimates from the U.S. Centers for Disease Control and Prevention suggest that the novel H1N1 virus has spread much further in the country and taken a far greater toll than earlier analyses suggested.

Now here’s some more bad news: CDC says manufacturers delivered far less pandemic vaccine this week than predicted.

According to new CDC estimates released today, about 22 million Americans have been infected with the virus, 98,000 have been hospitalized, and 3900 have died. Those data account for cases since the pandemic surfaced in April and run through 17 October. Until now, CDC has been reporting only H1N1 cases and deaths confirmed by lab tests. (As of 31 October, the cumulative numbers were 26,917 hospitalizations and 1265 deaths.) But confirmed cases are believed to be only a small portion of the true influenza burden. Many people never seek medical attention, and even if they do, they are not usually tested for the novel H1N1 virus. Some patients even die in hospitals from complications of an infection without making it into the statistics

by Jon Cohen

Concern appears to be rising at the U.S. Centers for Disease Control and Prevention about people in lower risk groups cutting in line to receive the limited supplies of H1N1 vaccine. A letter sent today from CDC Director Thomas Frieden to state and local health officers urges that the 35.6 million doses of the vaccine now available first go to people at the highest risk of developing severe disease from the pandemic virus. Although the letter does not detail any specific problems, it pointedly says, “vaccine distribution decisions that appear to direct vaccine to people outside the identified priority groups have the potential to undermine the credibility of the program.”

by Jon Cohen

With reporting by Martin Enserink.

Although the world’s attention is focused on the novel H1N1 virus causing the swine flu pandemic, H3N2, a seasonal strain of influenza, has popped up in many East Asian countries—and some variants in circulation may outfox the seasonal vaccine in use. “We have seen that H3N2 viruses have been in fairly broad circulation in some of the countries there,” Keiji Fukuda, special adviser on pandemic to the director-general of the World Health Organization, said at a press conference today.

The H3N2 strain is one of three in the seasonal influenza vaccines. But if the H3N2 strain in circulation differs substantially from the one used to make the vaccine, the vaccine may offer less protection, and more people will get sick than usual. “For the current H3N2, we don't have such studies, so I can't tell you right now the degree the current seasonal vaccine will protect against the H3N2 virus,” Fukuda says.

by Martin Enserink

It's a promise: 10% of the 250 million doses of H1N1 vaccine purchased by the United States will be donated to help poor countries. But when is still unclear. At a press conference today, Thomas Frieden, head of the U.S. Centers for Disease Control and Prevention, declined to answer questions about the timing of the gift. "That has to be determined as the production schedule will become more clear in the weeks to come."

WHO expects to send some 200 million doses of vaccines donated by countries and governments to the developing world. Timing is key, because the vaccine will do the most good if it's used before a wave of infection peaks. As WHO's Marie-Paule Kieny just told ScienceInsider, the United States has promised the first part of its share of 25 million doses by early December.

But AFP suggested last week that the United States will not donate any vaccine until it has taken care of the 159 million people in its priority groups.

by Martin Enserink

As the H1N1 swine flu pandemic marches on, western countries have begun vaccinating their most vulnerable populations against the virus. But many countries in the developing world lack the resources to buy the vaccine. With charitable donations from manufacturers and rich countries, the World Health Organization is trying to get cash-strapped countries at least some vaccine. Marie-Paule Kieny, head of WHO's Initiative for Vaccine Research, gave ScienceInsider an update on how this complex operation is moving along. Questions and answers have been edited for brevity and clarity.

Q: At a press conference last week, you said that WHO's plan to distribute vaccine to the developing world is now moving into its operational phase, and that WHO Director-General Margaret Chan has approved a list of 95 countries eligible for vaccine donations. Can we get a list of those countries?

M.-P.K.: No, because some of those countries may decide not to get the vaccine. So far, only about 40 countries have sent us a letter of intent saying they want us to send vaccine. Before we can make the names of the eligible countries public, we must know that they are willing to accept the conditions.

Q: What are those conditions?

M.-P.K.: They have to sign an agreement that they hold the vaccine manufacturers harmless in case of adverse events. WHO cannot bear that responsibility, so we're passing it on to the governments. It's the same as for most developed countries; they had to agree to this as well.

Q: Are the developing countries reluctant to accept that liability?

by Jon Cohen

U.S. policymakers erred on the side of caution in September when they recommended that children under 10 need two doses of the swine flu vaccine to develop a strong enough immune response to protect them from the disease. Now there’s strong evidence that they made the right call. New data also show for the first time that pregnant women need only a single shot.

At a press conference today, Anthony Fauci, head of the U.S. National Institute of Allergy and Infectious Diseases (NIAID), revealed the new data about these two groups, which are at high risk of developing severe disease from the novel H1N1 virus. As he explained, the trials tested the inactivated vaccine made in 389 children under 10 and in 50 pregnant women.

NIAID on 21 September reported preliminary data from the children’s study, which analyzed immune responses 8 to 10 days after participants received the vaccine and suggested the younger age brackets would need two doses. The new data confirm the preliminary findings.

by Jon Cohen and Martin Enserink

Health officials today reiterated that the novel H1N1 virus continues to spread rapidly around temperate zones of the Northern Hemisphere, hospitalizing and killing an unusual number of children, young adults, and pregnant women. The need for vaccine and antivirals remains pressing in these countries, and demand currently outstrips supply. Confusion also still complicates efforts to treat and prevent disease.

Between 1% and 10% of people who develop swine flu require hospitalization, according to a review of the current epidemiologic data released today by the World Health Organization (WHO). The new data were discussed 27–29 October at a meeting of WHO’s Strategic Advisory Group of Experts (SAGE) on Immunization. Up to 25% of hospitalized people are admitted to intensive care units, and between 2% and 9% die. Pregnant women make up 7% to 10% of hospitalized patients.

In a departure from official recommendations made elsewhere, SAGE announced that people regardless of age need only one dose of the H1N1 vaccine. The U.S. Centers for Disease Control and Prevention (CDC) recommends that children under 10 receive two doses. After the European Medicines Agency’s Committee for Medicinal Products for Human Use meeting 19–22 October, the agency recommended that everyone regardless of age receive two doses of the pandemic flu vaccines approved for use there. Granted, different vaccines are in use in different locales, but the differences reflect that data from clinical trials of various vaccines in a range of age brackets is still preliminary. And the dosing questions impact both the efficacy of the vaccines and their availability, given that they remain in short supply everywhere.

At a press conference held today by the CDC, its director, Tom Frieden, addressed the discrepancies about children under age 10. CDC based its decision for children under 10 to receive two doses on preliminary data from clinical trials of the vaccines being used in the United States, but he said more complete data should emerge soon. “Throughout this entire response, our approach is, look at the data and follow the data,” said Frieden.

Frieden also revealed new data about deaths in children.

by Jon Cohen 

Pandemics make strange bedfellows—in this case, public health advocates and defense hawks.

by Jon Cohen and Martin Enserink

The prospect that Americans will receive the swine flu vaccine in time to protect them from this second wave of the U.S. epidemic continues to dim. With the pandemic virus showing "widespread activity" in 47 states—six more than a week ago—the Centers for Disease Control and Prevention now concedes that many people will become infected before they have a chance to get the shot. "The vaccine will arrive too late for many," CDC Director Thomas Frieden said at a press conference this afternoon. But he noted that a third wave of disease may occur next winter, by which time there should be ample vaccine available.

Last week, Anne Schuchat, director of CDC's National Center for Immunization and Respiratory Diseases said 28 milion to 30 million doses might be ready by the end of October—a significant downward adjustment from the more than 40 million that Health and Human Services Secretary Kathleen Sebelius had predicted 3 weeks earlier. Although Frieden declined to make new projections for the weeks and months ahead, even those 28 million now seem unlikely. During the past 7 days, the number inched up from 11.4 million to 16.1 millions doses.