Opinion: Why is the norovirus such a huge problem for the NHS?

ljm67 — Fri, 13 Jan 2017 12:54:18 +0000

Norovirus, also known as winter vomiting disease, is on the rise again according to a report in the BMJ. A familiar set of warnings about ward closures and avoiding visits to patients in hospital was also issued, but why does this one virus cause the NHS such difficulty?

While norovirus does occur year-round, there is a winter peak in cases that clashes with the winter rush on the NHS. ̽��ֱ��symptoms of norovirus – diarrhoea and vomiting – typically last a day or two. While you may spend those days wishing you were dead, the chances of long-term harm from the infection are extremely low if you are otherwise healthy. ̽��ֱ��people most at risk from norovirus are the very young, the elderly and people with impaired immune systems (those said to be immunocompromised). Unfortunately, these are exactly the groups most likely to find themselves in hospital.

As a result of advances in transplant medicine and cancer treatment that suppress or affect the immune system, these immunocompromised patients make up an increasingly large portion of the population. While norovirus only lasts a few days at most in healthy people, those who are immunocompromised can struggle to clear the infection; it can linger for weeks, months or even years. Fortunately, it is rare that full-blown norovirus symptoms are experienced for this long. It does make it hard to absorb food and gain weight, which is a worry after major surgery and can make recovery much more difficult. As such these patients are a particular concern.

It is very easy to pass on the norovirus. One tablespoon of diarrhoea from a single patient can contain enough infectious virus to infect everyone in the world many times over. To make things worse, like many other viruses, people may remain infectious for several days after symptoms have resolved and not every infected person may even be symptomatic. Many cases are traced back to food handlers who may appear well and have no idea they are infectious. ̽��ֱ��virus can be spread through touching infected surfaces or material and a lack of suitable handwashing or hygiene before.

Outbreaks tend to occur in closed environments such as hospitals, cruise ships, schools and retirement homes, as these all share common dining and social areas and have many people eating food prepared by others. In the case of hospitals, many of these have a food court or canteen which is shared by staff, patients and visitors. In summer, many escape outdoors on lunch breaks to enjoy the weather. But in winter when norovirus peaks, everyone crowds together inside, away from the cold.

An expensive virus

Hospital staff are at an increased risk of catching norovirus themselves as they deal with large numbers of patients. This is not only unpleasant for the individuals concerned, but also means it’s possible for asymptomatic staff to spread the virus to patients and so exacerbate the problem. For this reason hospitals are very careful about decontamination, staff training, and discouraging ill staff from working for up to 48 hours after symptoms have resolved.

For an organisation which runs 24/7, and relies on a great deal of shift work, this can be very disruptive. All these disruptions come at a cost – lost hospital beds and closed wards, at a time when beds are already at a premium. In the two weeks before Christmas 2016, there were 15 hospital outbreaks of norovirus in the UK, 14 of which resulted in closed wards or restrictions on patient admissions. Past estimates of the costs of norovirus to the NHS put the total at over £100m (in 2002-03 prices). This is the same as employing over 3,000 extra specialist nurses, or around a third of the total cancer drugs budget.

̽��ֱ��cost to the global economy of norovirus has been estimated at a whopping US$44 billion, with US$4.2 billion of that to healthcare systems. At a time when NHS budgets are stretched, and hospitals are in debt, these additional costs are ones that hospitals can ill afford. With other seasonal and highly contagious diseases such as influenza, the NHS is able to offer and encourage its staff to take up free vaccinations in order to try and reduce the impact on staff, patient and visitor health. However, the absence of a vaccine means this is not yet an option for norovirus.

Vaccine trials are underway

While no drugs or vaccines are available, several vaccine candidates are in clinical trials. Sadly, immunity to norovirus does not last for long so, much like the flu vaccine, it is expected that regular vaccinations would be needed to make sure you remain immune. This would still be a huge benefit, and allow vaccination of workers at particular risk, or most likely to transmit the virus, such as NHS staff or those in the catering industry. ̽��ֱ��recent discovery of a means of growing different human norovirus strains in the lab, rather than having to rely on related animal viruses for research, will also boost efforts to find antivirals to help treat infection.

If you have norovirus, there is little your GP or hospital can do for you. ̽��ֱ��most a visit in person is likely to achieve is to spread the virus to other people. ̽��ֱ��NHS recommends that you stay at home, drink lots of water and, if you are concerned, phone your GP or NHS 111 for further advice.

Edward Emmott, Research Associate in Virology, ̽��ֱ�� of Cambridge

This article was originally published on ̽��ֱ��Conversation. Read the original article.

Writing for ̽��ֱ��Conversation, Edward Emmott, Research Associate in Virology explores why this notorious virus can cause the NHS such difficulty.

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Scientists take step towards drug to treat norovirus stomach bug

cjb250 — Tue, 21 Oct 2014 12:00:30 +0000

Norovirus is the most common cause of gastroenteritis in the UK. For most people, infection causes an unpleasant but relatively short-lived case of vomiting and diarrhoea, but chronic infection can cause major health problems for people with compromised immune systems. In many cases, patients who have weaker immune systems suffer from norovirus infection for months to years, with some patients experiencing gastroenteritis for as many as eight years. Outbreaks can cause significant economic losses – in UK hospitals alone, the cost of treating outbreaks is estimated at over £100 million a year, and foodborne outbreaks in the US lead to economic losses of around $2 billion per year.

̽��ֱ��virus is notoriously difficult to study because it will not grow efficiently in the laboratory, therefore scientists often use a mouse norovirus to identify drugs that can inhibit infection. It is one of a class of viruses known as RNA viruses, which have ribonucleic acid (RNA) as their genetic material. Most of the major viruses that have the potential to become epidemics are of this class. RNA viruses replicate and mutate rapidly, making them challenging to develop vaccines or immunity against.

In a study published today in the journal eLife and funded by the Wellcome Trust, a team of researchers led by Professor Ian Goodfellow has shown in mice with a long-term norovirus infection that the experimental drug favipiravir is effective at lowering levels of norovirus in the body, including in both tissue and faeces, which may help in reducing the severity of the disease and onward transmission.

Favipiravir is an experiment antiviral drug which is thought to be effective against a number of RNA viruses such as influenza, West Nile virus, yellow fever virus, and foot-and-mouth disease virus. It is currently also been tested as a potential drug to treat Ebola virus. ̽��ֱ�� ̽��ֱ�� of Cambridge team has shown that the drug works by causing the virus to self-destruct in a process known as ‘lethal mutagenesis’, which causes errors in the virus’s genetic information; because RNA viruses replicate and mutate rapidly, the errors take hold quickly, neutralising the virus and preventing further spread. This is one of the first demonstrations of lethal mutagenesis as a method of fighting viruses in their natural hosts and suggests that it may be possible to tackle other RNA viruses in the same way.

“Norovirus is an unpleasant bug that spreads quickly,” says Professor Goodfellow, a Wellcome Trust Senior Fellow, who led the study. “Most of us will have experienced it at some point and will know that the only option is to ride out an infection, drinking plenty of fluids. But some patients get infections that can last months or years, and this has a real impact on their quality of life. ̽��ֱ��ease with which infections spread, particularly in places such as hospitals, schools and cruise ships, and the potentially serious health problems norovirus can cause people with weakened immune systems means that we desperately need a way to treat infection.”

Dr Armando Arias, first author, adds: “Our work in mice is very promising and shows that favipiravir can make the virus mutate itself to death. It suggests that as well as treating infected individuals, the drug may also be useful in preventing infection during an outbreak. ̽��ֱ��next steps will be to test whether this drug is safe and effective at treating patients, too.”

Reference
Arias, A et al. Favipiravir elicits antiviral mutagenesis during virus replication in vivo. eLife; 21 Sept 2014.

An experimental drug currently being trialled for influenza and Ebola viruses could have a new target: norovirus, often known as the winter vomiting virus. A team of researchers at the ̽��ֱ�� of Cambridge has shown that the drug, favipiravir, is effective at reducing – and in some cases eliminating – norovirus infection in mice.

Our work in mice is very promising and shows that the drug favipiravir can make the virus mutate itself to death

Armando Arias