Published in the Sept. 11 issue of Science Express, the early online edition of the journal Science, the study – which includes the first estimate of the transmissibility of pandemic H1N1 influenza in schools – recommends that 70 percent of children ages 6 months to 18 years be vaccinated first, as well as members of high-risk groups as identified by the U.S. Centers for Disease Control and Prevention.
These groups include health care and emergency services personnel and those at risk for medical complications from pandemic H1N1 illness such as persons with chronic health disorders and compromised immune systems. Two doses of vaccine, delivered three weeks apart, may be needed to confer adequate protection to the virus.
Corresponding author Ira Longini, Ph.D., and colleagues emphasized that a combination of factors – the availability of an effective vaccine to protect people against pandemic H1N1, coupled with the timing of the outbreak – will determine how quickly the epidemic can be slowed. The researchers estimate that to bring the epidemic under control aggressive vaccination of the population must begin at least a month before the epidemic peak, concentrating on children as much as possible.
"Our estimates of pandemic H1N1 in households, schools and in the community places this virus in the higher range of transmissibility," said Yang Yang, Ph.D., first author of the paper and a staff scientist at VIDI.
Although social distancing and the use of antiviral medicines can be partially effective at slowing pandemic flu spread, vaccination remains the most effective means of pandemic influenza control, the authors conclude. From a cost effectiveness measure, vaccination remains the most effective, while closing schools and other social gathering places is the least cost effective.
Vaccination increases population-level immunity and lowers the effective reproductive number of the virus, which results in two main effects: slowing the spread of infection and reducing the height of the epidemic peak; and reducing the overall illness attack rate, hospitalizations and mortality.
Other key findings in the study:The current pattern of pandemic spread is most likely to be similar to the Asian influenza A (H2N2) pandemic of 1957-58. Substantial spread was expected to begin in early September with the epidemic peaking in mid to late October.
"In this case, child-first, phased vaccination would need to start as soon as possible, and no later than mid September to be effective for mitigation," said Longini, a biostatistician in the Center for Statistical and Quantitative Infectious Diseases at the Hutchinson Center. He is also a professor of biostatistics at the University of Washington School of Public Health. Longini said that the current U.S. plan called for the vaccination to probably start in mid October, which could still be effective if the epidemic peaked in November or December as it did during the Hong Kong influenza A(H3N2) of 1968-69.Children will experience the highest illness attack rates based upon epidemiological observations from the U.S. and around the world. In addition, from an outbreak of pandemic H1N1 at a private school in New York last April, the authors estimate that the typical student will infect an average of 2.4 other children in his or her school.
Many findings in this study are based on epidemiological studies and vaccine trails in the past for seasonal influenza vaccines.
"We would hope to be able to estimate the effectiveness of pandemic vaccines and other mitigation measures so that we can understand the control of pandemic H1N1 influenza," said M. Elizabeth Halloran, D.Sc., M.D., a co-author of the study and member of VIDI and professor of biostatistics at the University of Washington School of Public Health.
The predicted rate of pandemic H1N1 transmissibility – how many people an infected person will infect during influenza's infectious period in the beginning of an outbreak – is estimated to be 1.3 to 1.7. A value of 1.6 means that the epidemic could generate a total of 2.2 billion cases worldwide over a year. That translates to an overall illness attack rate of 32 percent of entire populations of a city or country. A person infected by someone else can expect to fall ill about two days after infection.
Longini and colleagues are considered among the world's leading disease modeling experts. They are part of the federal government's Models of Infectious Disease Agent Study (MIDAS) Network, an effort funded by the National Institute of General Medical Sciences at the National Institutes of Health.
Funding for the study came from the National Institute of General Medical Sciences and the National Institute of Allergy and Infectious Diseases.
Note to editors/reporters: To obtain a copy of the paper, "The Transmissibility and Control of Pandemic Influenza A (H1N1) Virus," please contact the Science press office at 202-326-6440 or firstname.lastname@example.org
At Fred Hutchinson Cancer Research Center, our interdisciplinary teams of world-renowned scientists and humanitarians work together to prevent, diagnose and treat cancer, HIV/AIDS and other diseases. Our researchers, including three Nobel laureates, bring a relentless pursuit and passion for health, knowledge and hope to their work and to the world. For more information, please visit fhcrc.org.
Dean Forbes | EurekAlert!
Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT
Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
08.12.2016 | Life Sciences
08.12.2016 | Physics and Astronomy
08.12.2016 | Materials Sciences