Wednesday, March 31, 2010

WHO sets up external panel to review pandemic response

From CIDRAP News Mar 29, 2010 by Lisa Schnirring - Staff Writer
The World Health Organization (WHO) today said it is in the final stages of putting together an independent committee to review its preparation for and response to the H1N1 pandemic, a group of about 29 experts that will meet for the first time in the middle of April.
Keiji Fukuda, MD, special advisor on pandemic influenza to the WHO director-general, shared details about the review group with journalists in Geneva. The WHO posted an audio recording of the press conference on its Web site.
Fukuda said the independent review will parallel another review effort within the WHO that will examine pandemic response as part of a required evaluation of how the International Health Regulations (IHR) functioned during the outbreak. He said the H1N1 pandemic was the first major test of the IHR, which are an agreement outlining how governments should handle global health emergencies.
Fukuda and other WHO health officials have often said the group looks forward to the lessons learned from its pandemic response. "The bottom line is how we can do better with our preparations and response," he said.
The review's timing isn't a signal that the pandemic is over, he said. Instead, the review comes one year into the pandemic, when health officials have accumulated a lot of experience with the response and the actions are still fresh in people's memories.
Some elected officials and health ministers have criticized the response of the WHO and governments, claiming that health officials overreacted to the disease threat and were influenced by pressure from pharmaceutical companies to buy vaccine stockpiles. The WHO and health authorities from several countries have strongly denied the claims.
The Council of Europe (COE) has launched its own inquiry into the WHO and governmental pandemic responses, and today in Paris the social, health, and family affairs committee of the COE's Parliamentary Assembly (PACE) held its second hearing on the issue. The COE, separate from the European Union, works on issues such as civil rights, economics, and democracy. The group was established after World War II and is made up of elected officials from 47 nations.
The WHO is still putting together the pandemic review group, which will have a broad range of expertise, including scientists and public health experts both inside and outside the infectious disease arena. Fukuda said that though the review group will operate independently from the WHO, members will be required, like the WHO's internal expert groups, to make declarations of interest and reveal potential conflicts of interest.
The group will hold its first meeting Apr 12 to 14. The committee will elect its own chair and cochair, set its own agenda, and seek out its own expert assessments. It will produce a preliminary report on its actions for the WHO director-general to present to the World Health Assembly in May.
Fukuda said the WHO anticipates that many countries will want to air their views with the new committee, and countries will have the opportunity to speak or submit written comments at the group's first meeting. Though there won't be a public gallery for the meetings, representatives from governments and other groups will be welcome to observe, and the WHO is still working out how to provide media access.
A final report on the WHO's pandemic response will likely be completed in time for the WHO director-general to present to the May 2011 World Health Assembly.
At today's COE hearing, Paul Flynn, a socialist member of the British Parliament, presented an initial inquiry report on the WHO's pandemic response. Flynn said the report reflects a recent meeting with Gillian Merron, Britain's public health minister. He said he will meet with WHO officials on Apr 15 to gather more information. COE said in a press release that the PACE committee will likely approve the report in late April, in advance of a possible debate on the topic in Strasbourg in June.
Today the committee focused on transparency issues related to the WHO and governmental pandemic responses. The group heard from Poland's health minister, Ewa Kopacz, about the country's decision not to buy pandemic vaccine.
Also on the agenda were Marc Gentilini, a member of France's National Academy of Medicine, who spoke on France's pandemic response; Dr Tom Jefferson, from the Cochrane Collaboration, who spoke on the use of scientific evidence when making flu-related decisions; and Michele Rivasi, a European Parliament member who is calling for that group to launch an inquiry. The European Parliament is an elected group and is one of the European Union's two legislative branches.

Friday, March 26, 2010

Study on Years of Life Lost to Pandemic Influenza

A new study argues that because the H1N1 influenza pandemic has cut many young lives short, its real public health impact has been substantially greater than is generally perceived.

In the study, a team of government and academic researchers came up with new estimates of deaths in the pandemic. By combining those with data on the age distribution of deaths, they estimated the number of "years of life lost" because of the pandemic. By that measure, its impact was at least as severe as a tough seasonal flu epidemic and possibly greater than the pandemic of 1968-69, they contend.

"We conclude that the 2009 A/H1N1 pandemic virus had a substantial health burden in the US over the first few months of circulation in terms of years of life lost, justifying the effort to protect the population with vaccination programs," says the report, published last night by PLoS Currents: Influenza. In the interest of rapid dissemination, the online journal publishes studies that have been screened by experts but have not undergone formal peer review.

Their report seeks to counter a popular view that the pandemic, at least to date, has been much "milder" than expected. This perception has prompted criticism that the threat was exaggerated by public health officials and by pharmaceutical companies hoping to profit from it. In particular, critics point to the Centers for Disease Control and Prevention (CDC) estimate that the pandemic has caused 12,000 deaths and note the CDC's own oft-quoted estimate that seasonal flu kills about 36,000 people annually.

The authors of the PLoS study contend that such comparisons are misleading, because the estimates were derived by different methods and because seasonal flu kills almost exclusively elderly people, whereas the H1N1 pandemic has primarily preyed on children and younger adults.

They sought to devise an "apples to apples" way to compare pandemic and seasonal flu mortality. To estimate the age distribution of pandemic deaths, they relied mainly on a European study of 468 laboratory-confirmed pandemic deaths, published in August 2009. It showed that more than 85% of the deaths were in people younger than 60, with an overall mean age of 37.4, as compared with an estimated mean age of 76 in those who die of seasonal flu.

The team then developed an estimate of pandemic deaths, given that only a fraction of cases and deaths are laboratory tested and that final statistics will not be available for another 2 to 3 years. This task involved comparing preliminary mortality data from the CDC's 122 Cities mortality surveillance system with final mortality data from the National Center for Health Statistics for 1999 through 2006. The team also used data on deaths in non-flu-season months to estimate the number of monthly deaths that would occur in the absence of flu.

Using these variables and the 122 Cities data for April through December 2009, the researchers estimated the pandemic death toll to be between 7,500 and 44,100. The lower number is based on deaths classified as due to pneumonia and influenza (P & I). The higher number is an estimate of "excess all-cause mortality, which is more inclusive as it also takes into account excess deaths from all respiratory and cardiovascular diseases that are associated with influenza infection, but may not be reported as such."

The team's range of estimates is considerably wider than the CDC estimate of between 8,500 and 17,600 H1N1 deaths in 2009. Viboud said the CDC estimate relies primarily on hospitalizations for lab-confirmed flu and related hospital deaths, with a correction for underreporting.

By applying the age-group mortality data from the European study to the estimated deaths, the researchers calculate that the pandemic took a toll of between 334,000 and 1,973,000 years of life lost (YLL).

The team used the same method of estimating flu-related deaths to come up with YLL estimates for previous pandemics and for seasonal flu. The results:

  • The 1968 pandemic, with 86,000 deaths and victims averaging 62.2 years old, caused 1,693,000 YLL.
  • The 1957 pandemic, with 150,600 deaths and a mean age of 64.6, caused 2,698,000 YLL.
  • The 1918 pandemic, with an estimated 1,272,300 deaths and a mean age of only 27.2, exacted a toll of 63,718,000 YLL.
  • An average flu season dominated by influenza A/H3N2—which generally causes more severe epidemics than other strains—causes 47,800 deaths and 594,000 YLL, with a mean age of 75.7.

Thus, the authors say, the lower end of their YLL estimate for the H1N1 pandemic is comparable to the estimate for an H3N2-dominated flu season, while the upper end is greater than that for the 1968 pandemic. Those impacts, of course, are dwarfed by that of the catastrophic 1918 pandemic.

"Based on US mortality surveillance data, we conclude that the YLL burden of the 2009 pandemic may in fact be as high as for the 1968 pandemic—but that at this time the assessment is still tentative," the report states. More waves of H1N1 cases are likely to come over the next few flu seasons, and later waves could be worse, it says. The 1968 pandemic is regarded as the least severe of the three 20th century pandemic and has been described as mild. But Viboud objected to the latter characterization.

"We do not like to use qualifiers such as 'mild,' 'moderate,' or 'severe' for influenza pandemics," she commented. "While the 1968 pandemic was associated with fewer deaths than the 1957 or 1918 pandemics, those deaths occurred in younger than usual age groups, as compared with typical seasonal influenza epidemics. By using the years of life lost metric, which takes into account both the number of deaths and their age distribution, the burden of the 1968 pandemic is estimated at about three times that of a typical influenza season in recent years, after adjusting for time trends in size and age structure of the US population."

In their report, the authors write that using terms such as mild, moderate, and severe to describe the health impact of seasonal and pandemic flu "is insufficient, and possibly inappropriate," because they are based on just one outcome measure: total deaths. "We recommend not using those terms anymore, because they really don't portray what happened," said Osterholm in an interview. "If there are 300,000 years of life lost, is that something mild?"

Terms like mild and moderate not only don't reflect YLL, but also fail to count lost work productivity when young people die and the pandemic's impact on hospital intensive care units, he added.

Concerning the CDC estimate of 36,000 deaths in an average flu season, Osterholm commented, "Those deaths in a traditional flu season are primarily in the elderly, where there's a question of how many cases you can prevent with vaccine anyway, whereas these [H1N1 pandemic deaths] are in a much younger population. From a public health perspective, it's clear that a death is not just a death."

"I think we can all agree that we'd all like to live long, healthy, prosperous lives, and anything that has a median age of death of 37 years is something that cuts short many healthy prosperous lives," he said. The researchers don't claim to have found a single outcome measure that best describes the impact of a pandemic, but say the YLL approach is the best for now.

Source: CIDRAP

Business Experts Share Lessons Learned on Pandemic Influenza

With pandemic flu activity declining over the past few months, businesses have a chance to retool some of their response plans, while many grapple with issues such as protective equipment shelf life and how to protect employees when pandemic or seasonal flu returns, corporate executives said today at a webinar.

Two business experts who spoke today said the pandemic plans their companies made back around 2005 helped minimize disruptions during recent pandemic H1N1 waves. Both speakers work for global companies that faced a variety of novel H1N1 situations across different parts of the world.

Scott A. Mugno, JD, managing director for FedEx Express Corporate Safety, Health, and Fire Prevention, said, "We were warned we'd have to go it alone, and that's what happened. Without planning we could have struggled, and we did not."

The webinar was sponsored by the University of Minnesota's Center for Infectious Disease Research and Policy (CIDRAP) Business Source, an online infectious-disease preparedness resource for businesses. It also featured Penny Turnbull, PhD, senior director for crisis management and business continuity planning for Marriott International, Inc.

Michael T. Osterholm, PhD, MPH, editor-in-chief of CIDRAP Business Source and director of CIDRAP, which publishes CIDRAP News, told webinar participants that, although influenza A activity is quiet, with no evidence of a third wave, business pandemic planners should keep in mind that the pandemic H1N1 virus is unpredictable. They should also be alert for other disease threats, such as H5N1 avian influenza, he said.

As business leaders reflect on their recent pandemic flu experiences, Osterholm advised them to think more broadly about its impact, aside from just categorizing it by severity level or number of deaths. He pointed out that the virus took its greatest toll on younger people, and an early analysis suggests that the current pandemic virus is killing people earlier in life, compared to past pandemic patterns.

"We need a new way to describe and measure pandemics that includes life lost, healthcare impact, and supply-chain impact," he said.

Turnbull said a new challenge that Marriott faced was how to extend consistent pandemic messaging across different brands of franchise hotels that it doesn't operate on a day-to-day basis. Marriott ended up making its pandemic flu materials to all of the sites with the expectations that guests expect the same message from all of the properties.

The heightened emphasis on keeping sick employees home also presented a challenge, she said. "In some cases we had to counsel managers that they could send sick employees home. We hope this becomes culturally acceptable at Marriott, not just during the pandemic."

Both Turnbull and Mugno said having a single corporate source for employee questions helped build confidence and minimize confusion, and they added that keeping the plans flexible was helpful, especially when the pandemic turned out to be mild to moderate, rather than the severe scenario many had planned for.

The two experts also emphasized that relationships with public health authorities were helpful and need to be refreshed and maintained. However, Mugno said vaccine availability caused some friction. He said media allegations of Wall Street firms getting some of the early doses has had a chilling effect on businesses hoping to secure doses to protect their risk groups, and he wishes that public health officials would have done more to defend the idea of making some of the vaccine available to the private sector.

Mugno said personal protective equipment stockpiles were "incredibly important" during the pandemic waves. The supplies not only played an important role in protecting employees, they provided a "comfort factor" for employees and customers. "They knew we had it, and it was ready to go," he said.

In the early days of pandemic flu spread, the company quickly realized it needed to move some of the supplies closer to employees in hard-hit areas such as Mexico, he added.

As businesses look ahead to the postpandemic phase, Turnbull advised business continuity planners to have discussions with leadership about tweaking and maintaining their pandemic plans. She emphasized how important it is for planners to show the value of risk assessment of factors that threaten education. "They [the leadership] don't know what they don't know. It's up to you to fill in the gaps," Turnbull said.

Both Mugno and Turnbull advised businesses to leverage their flu prevention messages with other events, such as national preparedness month in September.

Another next step is to keep vaccinating and to start making immunization plans for the next flu season, Mugno said, adding that public health workers at one FedEx site in Indiana recently went to the facility to administer the pandemic H1N1 vaccine. He advised businesses to use employee interest in the pandemic vaccine as a launching pad for future vaccine campaigns.

Osterholm agreed with the emphasis on vaccination, saying, "It's important to lay out and make available the vaccine."

Source: CIDRAP

WHO Says H5N1 Threat Persists

Newly confirmed human cases of H5N1 avian influenza, along with several outbreaks in poultry, are a reminder that the virus still poses a global threat, the World Health Organization (WHO) said yesterday.

So far this year the WHO has received 21 reports of human cases, seven of them fatal. Sixteen of the cases and five of the deaths were in Egypt. Vietnam and Indonesia have also reported infections and deaths. Poultry outbreaks have been reported by eight countries, many of which also reported human cases.

The WHO's warning came a day after another global group raised similar concerns. On Mar 23 an international avian influenza task force issued a statement expressing concern about waning interest and effort of governments and the public over the still-persistent H5N1 virus. The group aired its concerns at the end of a meeting at United Nation's Food and Agriculture Organization (FAO) headquarters in Rome.

The WHO said the virus is not only an immediate risk to those who handle birds, it could also reassort with another flu virus. Dr Takeshi Kasai, adviser for communicable disease surveillance and response in the WHO's Western Pacific office, emphasized in the statement that the influenza virus is unpredictable.

"In areas where H5N1 is endemic," he said, "WHO and its partners are working to build surveillance systems to identify changes in the behavior of the virus, raising awareness about the risks and protective measures, and building skills and capacity to respond to outbreaks quickly."

In a related development, animal health officials in Nepal reported H5N1 outbreaks at four locations in Banke district, in the western part of the country, the Himalayan Times reported yesterday. Authorities sent samples to Kathmandu for lab testing after a large number of birds died in the area. Rapid response teams were scheduled to begin culling operations today.

Nepal also reported an outbreak in late January that struck birds in Gandaki district, in the central part of the country, according to a report from the World Organization for Animal Health (OIE).


Findings, Gaps, and Future Direction for Research in Nonpharmaceutical Interventions for Pandemic Influenza

During March 4–6, 2009, principal investigators from eleven CDC funded studies met to share results, identify research gaps, and define future research needs to identify, improve, and evaluate the effectiveness of nonpharmaceutical interventions (NPIs) to mitigate the spread of pandemic influenza within communities and across international borders.

At the conference, the researchers expressed that NPI behaviors can be successfully taught to and adopted by a variety of persons through community health education, interactive classroom teaching, or Internet-based instruction. Urban Hispanics had misunderstandings about influenza (e.g., 88% thought that influenza was caused by bacteria), and their knowledge, attitudes, and practices improved through a community education program. Acceptability of NPIs also depends on early planning, consistent and targeted communication during implementation, and clear delineation of responsibilities and authority. Acceptability further requires communication from traditional (i.e., emergency response organizations) and nontraditional (i.e., churches) sources.

Behaviors perceived as typical daily behavior were more readily accepted than nontypical daily behaviors. Hand sanitizing with alcohol-based preparations, washing with soap, covering sneezes and coughs, and being aware of one's hands (e.g., touching face) showed relatively high compliance. Only 1 of 5 projects had good adherence to face mask use, which is not a typical behavior. In addition, efficacy of face masks for preventing transmission of influenza viruses has yet to be fully determined.

NPIs can be efficacious for reducing rates of influenza and influenza-like illness (ILI) in community settings. Household secondary attack ratios were substantially reduced if all household members practiced frequent hand washing and wore face masks within 36 hours after symptom onset in the index patient. University students had a 50%–65% reduced rate of ILI over a 6-week intervention period, using hand hygiene and masks. Mask use was substantial (4–5 hours per day average), which was attributed to adoption of masks as a daily behavior, rather than as a response to illness. Elementary school students using a 5-layered NPI approach, including hand hygiene and cough etiquette, had 53% fewer laboratory-confirmed influenza A infections and 26% fewer total absences compared with a control group.

Household crowding (measured as a deficit of >2 bedrooms) can be a factor in community influenza transmission, significantly increasing the relative risk (RR) for hospitalization for pneumonia or influenza (RR = 1.20, 95% CI 1.05–1.37; age standardized). The mean serial interval (i.e., the time between successive cases of infectious diseases in the chain of transmission) was 3.6 days, based on pairs of persons in 14 households.

School dismissal is part of CDC's pandemic planning, but dismissed students may congregate elsewhere. The number of social contacts by children dropped 67% (p<0.05)>

Rapid, large-scale risk-based entry screening of air travelers for ILI that used questionnaires and health assessments was conducted successfully at 2 airports for 177 flights. Seventy-five percent of passengers who provided contact details were followed up, but few of those with symptoms were prepared to go to a laboratory for collection of a respiratory specimen. On the basis of preliminary analysis, investigators concluded that voluntary travel restrictions would sufficiently protect only isolated populations with low numbers of visitors.

Meeting participants concluded that evidence exists of the effectiveness of NPIs, including face masks, hand hygiene, cough etiquette, reduced crowding, and school closures, in reducing the spread of influenza. Insufficient sample sizes, exacerbated by a mild influenza season during the first funding year, underreporting of disease, and challenges faced by influenza surveillance limited the statistical power of most studies. Further studies with larger sample sizes, common methods to allow pooling of data, and study durations that cover multiple influenza seasons are needed to address these limitations. In addition, studies using engineering controls, such as upper-room ultraviolet C lighting, in populations with naturally acquired infection are needed to address the relative contribution of transmission modalities, e.g., small vs. large respiratory droplets and contact transmission.

Source: CDC Emerging Infectious Diseases

Thursday, March 25, 2010

Studies compare 1918 and 2009 pandemic influenza viruses - potential vaccine design implications

We would like to reference the following article by Maryn McKenna, Contributing Writer for CIRAP News [Excerpts]:

Study shows 1918 and 2009 pandemic viruses share key feature

"Mar 24, 2010 (CIDRAP News) – Structural similarities between the pandemic flu viruses of 1918 and 2009 may explain older adults' apparent immunity to the newer virus, two scientific teams report today in two journals. Their results may also explain how pandemic viruses evolve into seasonal viruses, and could point the way toward development of future pandemic vaccines.

Writing in Science Express, the online ahead-of-print arm of the journal Science, Ian Wilson and Rui Xu of the Scripps Research Institute and colleagues from Vanderbilt University and Mount Sinai School of Medicine say that the 1918 and 2009 pandemic viruses are antigenically close, with hemagglutinin proteins that share similar crystalline structures. In contrast, the hemagglutinins in 24 seasonal flu strains dating from the 1930s through the 1950s, and 9 seasonal-vaccine strains from 1977 through 2007, differed from the pandemic strains by 30% to 58% of their amino-acid sequences.

The similarity between the two pandemic viruses is unusual, not only because they are separated by so many years, but also because genetic evidence has shown that the 2009 pandemic virus was not brand-new, but had already been circulating in humans—two circumstances that would have been expected to cause the viruses to diversify as they adapted.

The researchers said the unexpected similarity would have allowed the immune systems of those exposed to the 20th century virus to mount a defense against the 21st century one. ‘Our findings provide strong evidence that exposure to earlier viruses has helped to provide some people with immunity to the recent influenza pandemic,’ Wilson, who is Scripps Research Professor, said in a statement.

A second study, published on the website of Science Translational Medicine, adds significant detail to the understanding of the ways in which the two pandemic viruses are like each other and unlike seasonal flu strains.

Through a combination of computer modeling and experimental work, scientists at the National Institutes of Health (NIH) and the Centers for Disease Control and Prevention (CDC) determined that seasonal viruses possess, and the pandemic viruses lacked, a cap or covering of sugar molecules on the head of each organism's hemagglutinin.

…In a final experiment, the NIH and CDC researchers added glycan molecules to a 1918 virus, and used it as a vaccine in mice, which they then exposed to the "sugar-free" original 1918 strain. The altered virus conferred protection from the 1918 virus by stimulating the production of antibodies to which the original virus, lacking the sugar shield of later years, was vulnerable.
The researchers suggested that manipulating newly emerged viruses in such a manner could allow for the development of vaccines against future pandemic strains. If such vaccines were deployed, they said, the antibody protection produced could prevent a novel pandemic strain from becoming entrenched enough to evolve into a persistent seasonal flu. "

Article source: CIDRAP News

Xu R, Ekiert DC, Krause JC et al. Structural basis of pre-existing immunity to the 2009 H1N1 pandemic influenza virus. Science Express 2010 Mar 24 [Abstract]

Wei C-J, Boyington JC, Dai K et al. Cross-neutralization of 1918 and 2009 influenza viruses: role of glycans in viral evolution and vaccine design. Science Translational Med 2010 Mar 24 [Abstract]

NIH press release: 1918 and 2009 Pandemic Influenza Viruses Lack a Sugar Topping
Finding Could Aid Vaccine Design

Monday, March 22, 2010

H5N1 Avian Flu Outbreak in Nepal

Last week, the government of Nepal declared an emergency in Jhyalbas area in Nawalparasi district after a laboratory in the UK confirmed that samples from poultry that Nepal had sent for testing had been confirmed to be infected with H5N1 Avian Influenza (AI).

The District Livestock Office (DLO) said that they were planning to cull all birds, chickens, ducks and equipment used in the poultry farming in the areas. A district-level bird flu control committee chaired by the Chief District Officer today also launched a campaign to control the flu outbreak along with the declaration of the emergency. An emergency response team has also been formed under the coordination of Dr Laxman Dhakal.

According to Dr Dhakal, DLO has established a control room for the collection of chickens, ducks and other birds. Import and export of birds have been restricted and the government will compensate farmers for the culling of all poultry.

Earlier, symptoms of the flu were detected in Jhapa and Pokhara. The emergency response team claimed that the flu might have entered Jhyalbasi from Pokhara as a direct bus service is in operation between the two places. The team said that it will not take long to cull the birds, as the emergency area does not have any large poultry farms.

Meanwhile, Dr RS Dip, Chief of the District Public Health Office, says they are preparing to have the health of all locals assessed as soon as possible in order to detect any human AI cases.

Source: The Himalayan Times

Saturday, March 13, 2010

Influenza B virus circulation increases

Lisa Schnirring – Staff Writer, CIDRAP News reports:

‘Mar 12, 2010 (CIDRAP News) – Though pandemic flu is circulating at low levels in many parts of the world, Thailand and some West African nations are reporting increased activity, and the virus is being edged out by influenza B in China and other Asian regions, with signs of westward spread, the World Health Organization (WHO) said today.

Although surveillance information is limited in the West Africa area, the WHO said community transmission is occurring without any sign of a peak. Senegal, Cote D'Ivoire, and Rwanda are among the countries reporting increased flu activity, but so far little is known about the clinical patterns of the illnesses there, the group said in its weekly update.

Pandemic flu activity persists throughout South and Southeast Asia, with Thailand reporting the region's highest level of activity since the middle of January. Though about 25% of Thai patients with flu-like illness are testing positive for influenza, the WHO said the increase is well below the peak the country experienced last summer.
Mongolia reported a sharp increase in flu activity, attributed mostly to an increase in influenza B activity. Though pandemic flu activity declined in neighboring China, influenza B activity continued to increase.

Influenza B virus circulation seems to be moving westward, with the Russian Federation and Sweden now reporting that the virus is cocirculating with or dominating the pandemic virus. Iran also reported that, although flu activity is low, all recent detections have been influenza B.

Some countries reported increases in respiratory disease activity, though not all of it is thought to be pandemic flu, the WHO report said. For example, Afghanistan reported increased respiratory disease with a moderate impact on the country's health system. Bangladesh, Nicaragua, Honduras, and Brazil also reported similar increases.

The United States hasn't seen a spike in influenza B detections, though the US Centers for Disease Control and Prevention (CDC) said today that it is circulating at low levels. The nation saw a surge of influenza B cases near the end of the 2008-2009 flu season, which was problematic, because the B strain that was circulating didn't match the one contained in the seasonal flu vaccine. So far the influenza B strains identified at US labs this flu season are a good match for the current seasonal flu vaccine.

Vincent Racaniello, PhD, a virologist at Columbia University who writes Virology Blog, told CIDRAP News that the influenza B pattern the WHO is reporting is typical. He said the two main lineages, B/Victoria-like and B/Lee-like, have been cocirculating for 25 years, with changing patterns of prevalence and geographic distribution.
"There are frequent bottleneck years during which prevalence of B strains is low; this usually corresponds to high prevalence of influenza A strains," he said. "Once the bottleneck is relieved, there are usually changes in the prevalence of the two B lineages."

The current spread of influenza B may be a reflection of waning pandemic H1N1 activity that has occurred later in the Northern Hemisphere's flu season, Racaniello said.

Experts have noted that influenza B viruses in general cause less severe disease than influenza A and are associated with smaller disease clusters and illnesses in younger people, though hospitalizations and deaths from influenza B infections are seen in all age-groups.

In an accompanying update on oseltamivir-resistant pandemic H1N1 viruses, the WHO said it received no new reports of cases last week and said all have the H275Y substitution and are sensitive to zanamivir. The organization characterized the cases are sporadic, with rare onward transmission.’

Source: CIDRAP News

Monday, March 1, 2010

New H5N1 Antiviral and Vaccine

Researchers testing a new neuraminidase inhibitor for prevention and treatment of H5N1 influenza infection reported promising findings in a mouse study today, suggesting that the new antiviral may be effective even against oseltamivir (Tamiflu)-resistant strains. The international study group, headed by Dr Yoshihiro Kawaoka, is based at the University of Wisconsin in Madison, and their findings appear in Public Library of Science (PLoS) Pathogens. Previous animal studies of the neuraminidase inhibitor R-125489 and its prodrug CS-8958 have shown that the drug is effective against seasonal flu. In the new study, the group found that mice that were given a single intranasal dose of CS-8958 2 hours after experimental H5N1 infection had higher survival rates and lower virus levels than those given a standard 5-day course of oseltamivir. Also, mice that were given a single dose 7 days before infection with the virus were protected. The researchers also found that R-125489 bound more tightly to neuraminidase than any of the other drugs they tested.

In similar news, Hungarian and British researchers, writing in the February Journal of Virology, report that a single-dose, adjuvanted H5N1 influenza vaccine generated a good immune response in adult and elderly volunteers. In the trial, 480 people were randomly assigned to receive one or two 3.5-microgram (mcg) doses of the vaccine or one dose of 6 or 12 mcg. Single doses of 6 mcg or more triggered antibody responses that met European Union and US licensing criteria for flu vaccines, the report says. No unexpected adverse events were reported. "We found that the present vaccine is safe and immunogenic in healthy adult and elderly volunteers and requires low doses and, unlike any other H5N1 vaccines, only one injection to trigger immune responses which comply with licensing criteria," the report states. The vaccine, made by Omninvest of Hungary, contains an aluminum phosphate adjuvant.

This news comes as Vietnam announces it's third reported case in 2010 of human H5N1.

Source: CIDRAP News