Effects of flu on brain

Group of researchers from Germany and USA studied effects of influenza virus on brain cells. The study published in the Journal of Neuroscience finds that female mice infected with two different strains of the flu shows changes in structure and function of the hippocampus. These changes persist for one month after infection.

The long-term effect of influenza A virus infection on glial cell density and activation status within the hippocampal subregions. The neurotropic H7N7 IAV infection induced an increased microglia density in all hippocampal subregions at 30 days post-infection. Credit: Hosseini et al., JNeurosci

Influenza could present with neurological symptoms in some cases. So far research has not studied the long-term effect of the virus in the brain.

Researchers investigated three different influenza strains (H1N1, H3N2, H7N7). Two of these strains, H3N2 and H7N7, caused memory impairments that were associated with structural changes such as dendritic spine loss to neurons in the hippocampus. These changes persist up to 30 days following infection and fully recovered in 120 days.

Researchers feel that in the acute phase of influenza infection, this neuroinflammation in hippocampus alters the neuronal morphology and can cause cognitive deficits. The results also provide evidence that neuroinflammation induced by influenza virus infection can lead to longer-lasting alterations in neuronal connectivity with associated impairments in spatial memory formation.

Citation: Hosseini, Shirin, Esther Wilk, Kristin Michaelsen-Preusse, Ingo Gerhauser, Wolfgang Baumgärtner, Robert Geffers, Klaus Schughart, and Martin Korte. “Long-term neuroinflammation induced by influenza A virus infection and the impact on hippocampal neuron morphology and function.” The Journal of Neuroscience, 2018, 1740-17. doi:10.1523/jneurosci.1740-17.2018.

Research funding: Ministry of Science and Culture of Lower Saxony, Helmholtz-Association.

Adapted from press release by the Society for Neuroscience.

New flu simulation map using health and social media data

Researchers at the University of Chicago have created computer simulations to predict spread of flu across the United States utilizing datasets of demographics, healthcare visits and geographic movements of 150 million people over nine years. The study is published in the journal eLife.

Simulation map of flu spread. Credit: Andrey Rzhetsky, UChicago

Researchers utilized deidentified patient data from more than 40 million families in the US using Truven MarketScan to analyze insurance claims for treatment of flu-like conditions from 2003 to 2009. To get people movement data they used 1.7 billion geolocated twitter posts. Researchers also incorporated data on “social connectivity,” which is information about how often they visit friends and neighbors, air travel, weather, vaccination rates and changes in the flu virus itself.

The study results show that seasonal flu outbreaks originate in warm, humid areas of the south and the southeastern U.S. and move northward. The team utilized newer models based on all above variables to understand what factors drive the northward spread of the flu each year. In the paper, they liken the typical outbreak to a forest fire.

The researchers were able to use these models to recreate three years of historical flu data fairly accurately.

Citation: Chattopadhyay, Ishanu, Emre Kiciman, Joshua W. Elliott, Jeffrey L. Shaman, and Andrey Rzhetsky. “Conjunction of factors triggering waves of seasonal influenza.” ELife 7 (2018). doi:10.7554/elife.30756.

Research funding: National Institutes of Health, Defense Advanced Research Projects Agency, Liz and Kent Dauten.

Adapted from press release by the University of Chicago.

Computational model to track flu using Twitter data

An international team led by Alessandro Vespignani from Northeastern University has developed a computational model to predict the spread of the flu in real time. This unique model uses posts on Twitter in combination with key parameters of each season’s epidemic, including the incubation period of the disease, the immunization rate, how many people an individual with the virus can infect, and the viral strains present. When tested against official influenza surveillance systems, the model has been shown to accurately(70 to 90 percent) forecast the disease’s evolution up to six weeks in advance.

The paper on the novel model received a coveted Best Paper Honorable Mention award at the 2017 International World Wide Web Conference last month following its presentation.

While the paper reports results using Twitter data, the researchers note that the model can work with data from many other digital sources, too, as well as online surveys of individuals such as influenzanet, which is very popular in Europe.

“Our model is a work in progress,” emphasizes Vespignani. “We plan to add new parameters, for example, school and workplace structure.

Adapted from press release from the Northeastern University.

Role of Vitamin D in acute respiratory infections

Vitamin D supplements protect against acute respiratory infections including colds and flu, according to a study led by the Queen Mary University of London.

The study provides the most robust evidence yet that vitamin D has benefits beyond bone and muscle health, and could have major implications for public health policy, including the fortification of foods with vitamin D to tackle high levels of deficiency in the UK. The results, published in the BMJ, are based on a new analysis of raw data from around 11,000 participants in 25 clinical trials conducted in 14 countries including the UK, USA, Japan, India, Afghanistan, Belgium, Italy, Australia and Canada.

Individually, these trials yielded conflicting results, with some reporting that vitamin D protected against respiratory infections, and others showing no effect.

Lead researcher Professor Adrian Martineau from Queen Mary University of London said: “This major collaborative research effort has yielded the first definitive evidence that vitamin D really does protect against respiratory infections. Our analysis of pooled raw data from each of the 10,933 trial participants allowed us to address the thorny question of why vitamin D ‘worked’ in some trials, but not in others.”The bottom line is that the protective effects of vitamin D supplementation are strongest in those who have the lowest vitamin D levels, and when supplementation is given daily or weekly rather than in more widely spaced doses.

“Vitamin D fortification of foods provides a steady, low-level intake of vitamin D that has virtually eliminated profound vitamin D deficiency in several countries. By demonstrating this new benefit of vitamin D, our study strengthens the case for introducing food fortification to improve vitamin D levels in countries such as the UK where profound vitamin D deficiency is common.” Vitamin D – the ‘sunshine vitamin’ – is thought to protect against respiratory infections by boosting levels of antimicrobial peptides – natural antibiotic-like substances – in the lungs.

Overall, the reduction in risk of acute respiratory infection induced by vitamin D was on a par with the protective effect of injectable ‘flu vaccine against ‘flu-like illnesses. Vitamin D supplementation is safe and inexpensive, so reductions in acute respiratory infections brought about by vitamin D supplementation could be highly cost-effective.

Citation: Martineau, Adrian R., David A. Jolliffe, Richard L. Hooper, Lauren Greenberg, John F. Aloia, Peter Bergman, Gal Dubnov-Raz, Susanna Esposito, Davaasambuu Ganmaa, Adit A. Ginde, Emma C. Goodall, Cameron C. Grant, Christopher J. Griffiths, Wim Janssens, Ilkka Laaksi, Semira Manaseki-Holland, David Mauger, David R. Murdoch, Rachel Neale, Judy R. Rees, Steve Simpson, Iwona Stelmach, Geeta Trilok Kumar, Mitsuyoshi Urashima, and Carlos A. Camargo. “Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data.” Bmj, 2017, I6583. doi:10.1136/bmj.i6583.
Adapted from press release by the Queen Mary University of London.

Unvaccinated individuals cost more than 7 billion dollars a year in United States

Vaccine-preventable diseases among adults cost the U.S. economy $8.95 billion in 2015, and unvaccinated individuals are responsible for 80 percent, or $7.1 billion, of the tab, according to the most comprehensive analysis to date from the University of North Carolina at Chapel Hill.

Researchers at the UNC Eshelman School of Pharmacy, led by Associate Professor Sachiko Ozawa, studied 10 vaccines recommended by the Centers for Disease Control and Prevention. The study, which is published in the journal Health Affairs, examined the actual cost of inpatient and outpatient care, cost of medication and the value of productivity lost from time spent seeking care.

The 10 vaccines protect against hepatitis A, hepatitis B, the herpes zoster virus that causes shingles, human papillomavirus, influenza, measles, mumps, rubella, meningococcal disease, pneumococcal disease, tetanus, diphtheria, pertussis and chickenpox.

The flu was the most costly disease with a vaccine available, accounting for nearly $5.8 billion in health care costs and lost productivity in 2015. The Centers for Disease Control and Prevention estimates that 42 percent of U.S. adults received the flu vaccine during the 2015-2016 flu season. Other notable diseases with significant economic burdens include pneumococcal disease, such as meningitis and pneumonia, which is associated with nearly $1.9 billion in costs, and herpes zoster that causes shingles rounding out at $782 million.

“We believe our estimates are conservative and highlight the potential economic benefit of increasing adult immunization coverage and the value of vaccines,” Ozawa said. “We hope our study will spur creative health care policies that minimize the negative spillover effects from people choosing not to be vaccinated while still respecting patients’ right to make informed choices.”

The statistical model researchers developed determined the unvaccinated cost to the U.S. economy at $9 billion. Inpatient and outpatient care accounted for 95 percent of costs with lost productivity making up the other 5 percent.

The new UNC-led research is a more comprehensive review of the economic burden of vaccine-preventable diseases among U.S. adults than previous studies, as the focus to date has been on one or a few specific vaccine-preventable diseases. The researchers consulted existing research and data from the Medical Expenditure Panel Survey and the Nationwide Inpatient Sample database in their analysis.

Publication: Modeling The Economic Burden Of Adult Vaccine-Preventable Diseases In The United States.
DOI: http://dx.doi.org/10.1377/hlthaff.2016.0462 
Journal: Health Affairs – News
Research funding: Merck
Adapted from press release by University of North Carolina at Chapel Hill