The work is part of an effort, called the Models of Infectious Disease Agent Study (MIDAS), to develop computational models for conducting virtual experiments of how emerging pathogens could spread with and without interventions. The study involves more than 50 scientists with expertise in epidemiology, infectious diseases, computational biology, statistics, social sciences, physics, computer sciences and informatics.

As soon as the first cases of H1N1 infections were reported in April 2009, MIDAS researchers began gathering data on viral spread and affected populations. This information enabled them to model the potential outcomes of different interventions, including vaccination, treatment with antiviral medications and school closures. The work built upon earlier models the MIDAS scientists developed in response to concerns about a different potentially pandemic influenza strain H5N1 or avian flu.

“Computational modeling can be a powerful tool for understanding how a disease outbreak is unfolding and predicting the implications of specific public health measures,” said Jeremy M. Berg, Ph.D., director of the National Institute of General Medical Sciences, which supports MIDAS. “During the H1N1 pandemic, MIDAS scientists applied their models to see what they could do to help in a real situation.”

Because the H1N1 flu strain is still circulating, a MIDAS group based at the University of Washington in Seattle is now studying the impact the virus could have this fall and winter. Its model, which represents the world population, includes information about immunity – how many people are protected by vaccination or prior infection-and the other circulating flu strains. Using the model, the scientists may be able to predict how H1N1 evolves and the possible role of the H3N2 strain, which historically has been the dominant seasonal flu virus. The results also may help forecast the potential effectiveness of the new flu vaccine that includes both the H1N1 and H3N2 viral strains.

Here are key findings from MIDAS’ earlier work on the H1N1 pandemic. For more results and links to the scientific papers, visit http://www.nigms.nih.gov/Initiatives/MIDAS/Publications.htm.

Estimating Severity

To predict the likely severity of H1N1 in the fall and winter months following the initial outbreaks, the MIDAS group led by Marc Lipsitch, D.Phil., of the Harvard School of Public Health in Boston analyzed patient care data from Milwaukee and New York City. The researchers estimated that about 1 in 70 symptomatic people were admitted to the hospital, 1 in 400 required intensive care and 1 in 2,000 died. They predicted H1N1 to be no more and possibly even less severe than the typical seasonal flu strain. The work, which factored in local differences in flu detection and reporting, also showed that it’s possible to make predictions about severity using data from the early stages of an outbreak.

Vaccinating Children

Ira Longini, Ph.D., at the University of Washington and his MIDAS colleagues developed a simulation model to evaluate the effectiveness of different strategies to vaccinate school-aged children, who are known to play a key role in transmitting the flu virus. They modeled a range of scenarios that varied the type of vaccine, the percentage of children vaccinated and the infectiousness of the virus. For each situation, the modeling results indicated that vaccinating this age group substantially reduced overall disease spread and prevented up to 100 million additional cases in the general population. These effects, however, were less strong when the virus was more contagious or when fewer children were vaccinated. Based on these results, Longini’s group concluded that vaccine distribution strategies should depend on a number of factors, including vaccine availability and viral transmission rates.

Cost-Benefit of Employee Vaccination Programs

In one of the first analyses of the economic value of work-sponsored seasonal and pandemic flu vaccine programs, the MIDAS group led by Donald Burke, M.D., at the University of Pittsburgh developed a model that estimated the employer cost to be less than $35 per vaccinated employee with a potential savings of $15 to $1,494 per employee, depending on the infectiousness of the virus.

Interventions and Local Demographics

To determine if a vaccination strategy would likely have the same effect in different locations, a team led by MIDAS investigator Stephen Eubank, Ph.D., of the Virginia Bioinformatics Institute at Virginia Tech in Blacksburg developed models representing the demographics of Miami, Seattle and each county in Washington. The models indicated that while vaccinating school-aged children was the best strategy in each place, the optimal timing and overall effectiveness of the approach varied due to specific characteristics of the local population, such as age, income, household size and social network patterns. These differences, Eubank concluded, suggest that vaccination and probably other intervention strategies should take local demographics into account.

Antiviral Medications

Lipsitch’s collaborators Joseph Wu, Ph.D., and Steven Riley, D.Phil., at the University of Hong Kong used mathematical modeling to predict the likelihood that the H1N1 strain would develop resistance to the widespread use of antiviral medications taken to lessen flu symptoms. Their work showed that giving a secondary antiviral flu drug either prior to or in combination with a primary antiviral could mitigate the emergence of resistant strains in addition to slowing the spread of infection. The results, the researchers concluded, point to the value of stockpiling more than one type of antiviral drug.

School Closures

A public health measure under consideration was closing schools, which previous MIDAS pandemic flu models identified as a potentially effective intervention. According to Burke’s model of Allegheny County, Penn., closing individual schools after they identified cases may work as well as closing entire school systems. When strictly maintained for at least 8 weeks, both types of school closure could delay the epidemic peak by up to 1 week, allowing additional time to develop and implement other interventions. However, the model also indicated that school closures lasting less than 2 weeks could actually facilitate flu spread by returning susceptible students to school in the middle of an outbreak.

“Models like the ones MIDAS has developed help us understand not only trends in disease spread, but also how different factors can influence those trends,” said Irene A. Eckstrand, Ph.D., who directs the MIDAS program. “MIDAS research is leading to new tools and approaches that can aid in making public health decisions at a range of levels, from local to national.”

To learn more about MIDAS, visit http://www.nigms.nih.gov/Initiatives/MIDAS/. To arrange an interview with NIGMS Director Jeremy M. Berg, Ph.D.; MIDAS Director Irene A. Eckstrand, Ph.D.; or MIDAS scientists, contact the NIGMS Office of Communications and Public Liaison at 301-496-7301.

NIGMS is a part of NIH that supports basic research to increase our understanding of life processes and lay the foundation for advances in disease diagnosis, treatment and prevention. For more information on the Institute’s research and training programs, see http://www.nigms.nih.gov.

The National Institutes of Health (NIH) – The Nation’s Medical Research Agency – includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

What is the H1N1 virus?

H1N1 is currently the predominant strain of circulating flu virus. It is similar to other flu viruses in terms of how the body responds and the severity of the illness. What is different is that it is a new strain, so the body doesn’t have natural immunity, and it may cause serious illness in some cases.

What are the Symptoms of H1N1?

Signs of H1N1 are flu-like and present as an acute respiratory illness. Symptoms include sudden onset of fever and/or cough along with possible headache, muscle and joint pain, fatigue sore throat and runny nose, and sometimes vomiting and diarrhea.

How does H1N1 spread?

The virus is spread from person-to-person. It is transmitted as easily as the normal seasonal flu and can be passed to other people by exposure to infected droplets expelled by coughing or sneezing that can be inhaled (within 6 feet), or that can contaminate hands or surfaces.

Naturopathic Recommendations for avoiding H1N1:

-The most important prevention method that is often overlooked is good hygiene, specifically frequent handwashing. Some researchers believe that hand sanitizers are effective at preventing transmission, however, the research is conflicting and proper handwashing is still the number one recommendation.

-Minimize or avoid sugar consumption – One of sugar’s major drawbacks is that it raises the insulin level, which inhibits the release of growth hormones, which in turn depresses the immune system.

-Exercise – regular exercise has a direct immune boosting affect

-Reduce stress – chronic, severe, long term stress takes a toll on our adrenal glands, our stress glands. Under normal amounts of stress, our adrenal glands function as they should, releasing hormones such as adrenaline and cortisol which help to regulate many normal bodily functions. However, when our adrenal glands go into overdrive, they eventually shut down and this can adversely affect many systems including our immune systems allowing viruses to enter our bodies.

-Get lots of sleep – research shows that lack of good quality sleep prevents regulation of key chemicals produced by the immune system to fight infection and say that sleep and the immune system are closely linked.

-Probiotics – studies have shown that supplementation of good bacteria can decrease the symptoms of upper respiratory infections.

-Vitamin D – vitamin D levels decrease during the winter months, the same time that seasonal influenza rates are at their highest. Therefore it is beneficial to have serum 25(OH) vitamin D3 levels tested during the winter time and if levels are found to be low, then daily supplementation of 3,000-5,000 IU is beneficial. For children, a recommended dose is 1,000-2,000 IU daily.

-Homeopathic remedies – Influenzinum is a good general homeopathic that can be used to prevent the seasonal flu, however it is best to see a Naturopathic doctor to determine if this is the right remedy and to prescribe the correct dose and potency.

Dr. Marni Ross, is a licensed Toronto Naturopathic Doctor (ND) specializing in Digestive Disorders, Allergies, Skin Disorders, Women’s Health, Perinatal Care and other chronic conditions. For more information on Toronto Naturopathic Medicine and Acupuncture visit www.marnirossnd.com