Encephalitis, Tick-Borne

The number of infections by the tick-borne TBE virus that are not detected by health services is far higher than previously assumed. This has been shown in a new study of Swedish blood donors. The number of infections by the tick-borne TBE virus that are not detected by health services is far higher than previously assumed. This has been shown in a new study of Swedish blood donors from Uppsala University and the University Hospital in Uppsala. The results have been published in the journal Eurosurveillance, which is associated with the EU's Centre for Disease Prevention and Control. "We were very surprised that such a high proportion of the blood donors showed traces of a previous TBE virus infection. This is far more than could have been suspected based on the number of reported cases," says Bo Albinsson, doctoral student at Uppsala University, one of the first authors of the article. Tick-borne encephalitis (TBE) is a very serious disease that is increasingly common in large parts of Europe. According to statistics from the Public Health Agency of Sweden, 597 cases of the disease had been reported in Sweden by November 2023, the highest number ever registered in a single year. TBE has been a notifiable disease since 2004 under the Communicable Diseases Act and all cases must therefore be reported to the regional infection control doctor and the Public Health Agency of Sweden. However, people who only develop mild symptoms or no symptoms at all are not detected by the health services and therefore do not show up in the statistics. Until now, the relationship between the number of reported cases and the proportion of people infected was unknown. Traditional methods of investigating whether someone has previously been infected by the virus are not completely reliable as individuals who have been vaccinated against TBE can also test positive. On top of this, it is not known exactly how many people have been vaccinated, since Sweden has no national vaccination register for TBE. In the new study, the result of a Swedish collaboration, the researchers have investigated blood tests from 2,700 anonymous blood donors from nine regions in Sweden. The method they used is called TBE-SMIA (suspension multiplex immunoassay) and was developed at the Zoonosis Science Center (ZSC) at Uppsala University in collaboration with the Clinical Microbiology Department at Uppsala University Hospital. It makes it possible for the first time to effectively distinguish the antibody response after TBE virus infection from the response after TBE vaccination. This has enabled the researchers to identify how many people have had the infection. They were also able to estimate the proportion of the population in each region that is vaccinated. The results showed that the proportion of blood donors with a history of TBE virus infection varied from 1 per cent to 7 per cent between the different regions. Based on the population sizes of the regions, the researchers estimated that this corresponds to a total of more than 160,000 people aged 15-65, which is significantly higher than previous estimates. The researchers also found that the proportion of blood donors vaccinated against TBE varied between 8.7 per cent and 57 per cent in the different regions. In total, this translates to over 1.6 million Swedes (aged 15-65) in the regions investigated. "It is noteworthy that the number of confirmed TBE cases is increasing despite relatively good vaccination coverage. Further research is therefore needed, for example by carefully mapping the distribution of the virus in different tick populations. Our results provide an important background for future vaccination strategies and we believe it would be well worth considering establishing a national vaccination register for TBE," says Tove Hoffman, researcher at the ZSC and the study's other first author.

Dive Brief:Bavarian Nordic will stop developing an experimental vaccine for respiratory syncytial virus, or RSV, after the shot failed to meet one of the key goals of its Phase 3 trial.Study results disclosed on Saturday showed the vaccine was only about 43% effective at preventing severe instances of respiratory disease caused by RSV, defined as including at least 3 symptoms, in adults 60 years of age or older. The vaccine was more protective against more mild cases that included at least two symptoms, but Bavarian Nordic nonetheless intends to stop development, including an ongoing partnership with Nuance Pharma.The Danish biotechnology company believes the revenue generated from a portfolio of travel vaccines it recently acquired from Emergent BioSolutionscan help offset the loss of milestone payments it couldve received from Nuance. Still, shares lost more than a quarter of their value in Monday trading, falling to their lowest levels since May 2022.Dive Insight:The bar for a successful RSV vaccine has been raised significantly in the last few months.Since May, Pfizer and GSK have both brought RSV vaccines to market, and AstraZeneca and Sanofi have followed with a protective antibody drug.Moderna has brought a shot to regulators as well, highlighting the fierce competition Bavarian Nordic has been up against. Already, one competitor, Johnson & Johnson, has bowed out despite having a vaccine in late-stage development. The Danish biotech is now following suit.Its decision comes as the result of a Phase 3 study in more than 20,000 adults at least 60 years of age, a similar group to the one now cleared to receive Pfizer and GSKs vaccines. The shot did meet one of its study goals, proving 59% effective at preventing at least two lower respiratory tract disease symptoms. But missing its other goal was unexpected, said the companys president and CEO, Paul Chaplin, in a statement.While the outcome will impact our short-term growth expectations, we continue to have a unique commercial business and given the recent strong brand and market growth, this provides a solid foundation for profitable growth in the years to come, Chaplin said.The company sells a portfolio of vaccines already, including shots for tick-borne encephalitis, smallpox and monkeypox, and acquired other products from Emergent for typhoid fever and cholera. As a result, its not expecting the study failure to have any impact on its financial projections for 2023.The company could also add to its product portfolio shortly. A vaccine for chikungunya virus recently succeeded in a late-stage study.There arent any shots or treatments available for chikungunya virus infections. '

THURSDAY, May 25, 2023 – Robert Weymouth, 58, of Portland, Maine, died this year because of a tick bite. You've likely heard of Lyme disease and the problems it can cause when passed to a human through the bite of a deer tick. But Lyme isn’t the only tick-borne illness in the woods. Powassan virus -- a rare and untreatable infection -- is also transmitted by ticks. That's the bite that led to fatal complications in the case of this Maine truck driver. Weymouth -- the third Powassan death since 2015 in Maine and the first this year -- likely contracted the virus in the state, according to Maine's Centers for Disease Control and Prevention. He developed neurological symptoms and died in the hospital. His widow, Annemarie Weymouth, is now warning others about protecting themselves from the illness. "He was in there, but he couldn't move his body. He could point to words on a board. He pointed to 'scared,' 'afraid,' 'frustrated,'" Weymouth told CBS News . True case numbers unknown “Because it's relatively rare to make the diagnosis, there's a lot we don't know,” said Dr. Eugene Shapiro , a professor of pediatrics and epidemiology at Yale University. But here's what is known: The U.S. Centers for Disease Control and Prevention received 189 reports of Powassan infection between 2012 and 2021. Most U.S. cases of Powassan virus happen in the Northeast and Great Lakes regions. Maine had four cases last year alone. Though ticks are arachnids like spiders, the virus is not so different from some viruses in which a mosquito is the vector, such as dengue and Zika. Other than its transmission by a tick, Powassan virus is “in no way, shape or form anything like Lyme disease,” Shapiro said. Powassan virus is closely related to something called tick-borne encephalitis, which is a virus particularly seen in Central Eastern Europe and Eurasia, Shapiro said. The Powassan virus severely affects only a small number of people each year. But it's possible many others are asymptomatic or have minor or flu-like symptoms and aren’t diagnosed. The virus got its name from its discovery in a 5-year-old boy who died of the virus in the late 1950s in Powassan, Ontario, Canada. Experts think it used to be transmitted primarily by the groundhog tick, which typically did not feed on humans. Instead, it fed mostly on skunks, groundhogs and squirrels, Shapiro said. At some point, it moved to deer ticks, and those are ticks that commonly bite humans. Brain inflammation There are still many mysteries to unravel concerning Powassan virus. For example, although some research has suggested that as many as 5% of deer ticks in some areas of Connecticut are positive for the virus, that’s not showing up in high numbers of Powassan human infection, Shapiro said. But cases are rising, according to CDC numbers, said Dr. Nicole Baumgarth , an immunologist at Johns Hopkins School of Public Health. Yet it’s not clear whether there are actually more people becoming infected or if doctors are testing for it more frequently, she said. “There is no treatment, other than sort of general support of an individual who has the disease,” Baumgarth said. “The most serious illness associated with Powassan is inflammation of the brain, or encephalitis, but not everybody who gets infected with this virus will develop these very severe cases.” Other symptoms can include fever, chills, fatigue, rash on trunk of the body, muscle weakness, nausea, vomiting, dizziness and neck stiffness, according to Yale Medicine. However, the vast majority of those infected likely will have no symptoms or minor symptoms and not be diagnosed. For those who do have symptoms severe enough to be diagnosed, typically with encephalitis, the death rate is somewhere between 10% and 30%, Shapiro said. Keep in mind, however, it is rare. "It is a little scary, but it is a rare disease,” Baumgarth said. With Lyme disease, the tick has to be attached for about a day or so to transmit its infection. Pulling the tick off promptly puts you at low risk of infection. If it’s been longer, a single dose of doxycycline is moderately effective in preventing infection. However, Baumgarth noted that the Powassan pathogen can be transmitted faster than Lyme bacteria, "so it's hard to outrun that." Prevention is the best cure You can take some precautions to limit tick exposure when spending time in grassy or wooded areas that can harbor ticks, Baumgarth and Shapiro said. Wear long sleeves and long pants, with the bottoms of the pants tucked inside socks. Wear light-colored clothing so that any ticks might be visible. Remove them right away. Use an insect repellent that has 30% DEET. Another repellent, permethrin, is meant to be applied to clothing. After you return from hiking, wash clothes and place in a hot dryer. If it’s hot enough, that will kill ticks. Check yourself for ticks after you return, shower immediately and have someone else check in places you can’t see, if possible. Sources Eugene Shapiro, MD, professor, pediatrics and epidemiology, vice chair for research, Department of Pediatrics, and deputy director, investigative medicine PhD program, Yale University, New Haven, Conn. Nicole Baumgarth, DVM, PhD, immunologist, Johns Hopkins School of Public Health, Baltimore CBS News Posted May 2023