Latest news with #R0
The Sun
04-08-2025
- Health
- The Sun
The ‘most contagious diseases' revealed – and the one in first place could be about to surge in the UK
WE'RE all familiar with the contagious nature of illnesses like the common cold and flu. If someone infected with one of these viruses sneezes, cough, sings, or talks nearby you, the likelihood of you catching what they've got is pretty high. 2 But there are more contagious illnesses in existence definitely worth knowing about. The one that takes the top spot for being most contagious is measles. According to Dan Baumgardt, senior lecturer at the School of Physiology, Pharmacology and Neuroscience, University of Bristol, it's all based on R0 - a measure of how many other people are likely to become infected from another. He said: "The R0 measure indicates how an infection will spread in a population. "If it's greater than one, the outcome is disease spread. "An R0 of one means the level of people being infected will remain stable, and if it's less than one, the disease will often die out with time." Measles has made a resurgence globally in recent years, including in the UK - and its R0 is considered high. While several factors are said to contribute to this, the primary cause is a decline in childhood vaccination rates. Writing for The Conversation, Baumgardt said this drop has been driven by disruptions such as the Covid pandemic and global conflict, as well as the spread of misinformation about vaccine safety. He continued: "The R0 number for measles is between 12 and 18. If you do the maths, two cycles of transmission from that first infected person could lead to 342 people catching the illness. "That's a staggering number from just one patient – but luckily, the protective power of vaccination helps reduce the actual spread by lowering the number of people susceptible to infection. Measles is extraordinarily so infectious that an unvaccinated person can catch the virus just by entering a room where an infected person was present two hours earlier. "People can also be infectious and spread the virus before they develop symptoms or have any reason to isolate." Just last week, health officials from the UK Health Security Agency (UKHSA) voiced fears that another surge of measles cases could be on the way. Since January 1, there have been 674 laboratory confirmed measles cases reported in England, with 48 per cent of these cases in London, 16 per cent in the North West, and 10 per cent in the East of England. And holiday travel and international visits to see family this summer could lead to rising measles cases in England when the new school term begins, the UKHSA warned. 2 The main symptoms of measles MEASLES is highly contagious and can cause serious problems in some people. The infection usually starts with cold-like symptoms, followed by a rash a few days later. The first signs include: A high temperature A runny or blocked nose Sneezing A cough Red, sore, watery eyes Small white spots may then appear inside the cheeks and on the back of the lips. A rash tends to come next. This usually starts on the face and behind the ears before spreading to the rest of the body. The spots are sometimes raised and join together to form blotchy patches. They are not normally itchy. The rash looks brown or red on white skin. It may be harder to see on darker skin. Complications are rare, but measles can lead to pneumonia, meningitis, blindness, seizures, and sometimes death. Source: NHS As Baumgardt mentioned, one of the best ways to protect yourself from measles is to get vaccinated. The first measles mumps and rubella (MMR) vaccine is offered to infants when they turn one year old and the second dose to pre-school children when they are around three years and four months old. Around 99 per cent of those who have two doses will be protected against measles and rubella. Other infectious diseases Other infectious diseases with high R0 values, said Baumgardt, include pertussis/whooping cough (12 to 17), chickenpox (ten to 12), and Covid, which varies by subtype but generally falls between eight and 12. He said: "While many patients recover fully from these conditions, they can still lead to serious complications, including pneumonia, seizures, meningitis, blindness, and, in some cases, death." But be wary of those with a lower infectivity rate - as it doesn't necessarily mean it's less dangerous, said Baumgardt. For example, tuberculosis (TB) has an R0 ranging from less than one up to four. But the danger lies in how difficult it is to treat. Baumgardt warned: "Once established, it requires a combination of four antibiotics taken over a minimum of six months. Standard antibiotics like penicillin are ineffective, and the infection can spread beyond the lungs to other parts of the body, including the brain, bones, liver and joints. "What's more, cases of drug-resistant TB are on the rise, where the bacteria no longer respond to one or more of the antibiotics used in treatment." Expert answers MMR questions TO help deal with parental concerns, Professor Helen Bedford, a specialist in child public health at University College London, tells you all you need to know about the MMR vaccine. When is the vaccine given? The MMR vaccine is part of the NHS Routine Childhood Immunisation Programme. It's typically given via a single shot into the muscle of the thigh or the upper arm. The first dose is offered to children at the age of one (babies younger than this may have some protection from antibodies passed on from their mother, which start to wear off at about 12 months.) The second dose is then offered to children aged three years and four months before they start school. To check to see if you or your child have had the recommended two doses of MMR, you can look at their/your Personal Child Health Record, also known as the red book. If you can't find the red book, call your GP and ask them for your vaccine records. You are never too old to catch up with your MMR vaccine. If you see from your vaccination records that you did not receive two doses as a child, you can book a vaccination appointment. Is the vaccine safe? The MMR vaccine is safe and effective at preventing measles, mumps and rubella. In the UK, we started using the jab in 1988, so we have decades of experience using it. The jab is made from much-weakened live versions of the three viruses. This triggers the immune system to produce antibodies that are protective in the face of future exposure. It takes up to three weeks after having the vaccine to be fully protected. Like any vaccine, the MMR jab can cause side-effects, which are usually mild and go away very quickly. This includes rash, high temperature, loss of appetite and a general feeling of being unwell for about two or three days. There is also a very small chance children can have a severe allergic reaction. But compared to the complications of measles, there is no contest that vaccination is by far the safest and most effective route to take. Why was it linked with autism? In 1998, Andrew Wakefield and his colleagues published a now-discredited paper in medical journal The Lancet. The paper suggested that the MMR vaccine might be associated with autism and a form of bowel disease. It led to a sharp decline in vaccination rates. Even at the time, the research was considered poor. The Lancet retracted the story in 2010 after Wakefield's article was found 'dishonest' by the General Medical Council. He was later struck off and subsequently, in 2011, the British Medical Journal declared the story fraudulent. Does it contain ingredients from pigs? There are two types of MMR jabs: One with gelatin (animal/pig collagen), and one without it. For some religious groups, the inclusion of pig products is not acceptable. Those people should ask for the vaccine without gelatin.
Yahoo
01-08-2025
- Health
- Yahoo
The contagion scale: which diseases spread fastest?
When the COVID pandemic hit, many people turned to the eerily prescient film Contagion (2011) for answers – or at least for catharsis. Suddenly, its hypothetical plot felt all too real. Applauded for its scientific accuracy, the film offered more than suspense – it offered lessons. One scene in particular stands out. Kate Winslet's character delivers a concise lesson on the infectious power of various pathogens – explaining how they can be spread from our hands to the many objects we encounter each day – 'door knobs, water fountains, elevator buttons and each other'. These everyday objects, known as fomites, can become silent vehicles for infection. She also considered how each infection is given a value called R0 (or R-nought) based on how many other people are likely to become infected from another. So, for an R0 of two, each infected patient will spread the disease to two others. Who will collectively then give it to four more. And so a breakout unfolds. The R0 measure indicates how an infection will spread in a population. If it's greater than one (as seen above), the outcome is disease spread. An R0 of one means the level of people being infected will remain stable, and if it's less than one, the disease will often die out with time. Circulating infections spread through a variety of routes and differ widely in how contagious they are. Some are transmitted via droplets or aerosols – such as those released through coughing or sneezing – while others spread through blood, insects (like ticks and mosquitoes), or contaminated food and water. But if we step back to think about how we can protect ourselves from developing an infectious disease, one important lesson is in understanding how they spread. And as we'll see, it's also a lesson in protecting others, not just ourselves. Here is a rundown of some of the most and least infectious diseases on the planet. In first place for most contagious is measles. Measles has made a resurgence globally in recent years, including in high-income countries like the UK and US. While several factors contribute to this trend, the primary cause is a decline in childhood vaccination rates. This drop has been driven by disruptions such as the COVID pandemic and global conflict, as well as the spread of misinformation about vaccine safety. The R0 number for measles is between 12 and 18. If you do the maths, two cycles of transmission from that first infected person could lead to 342 people catching the illness. That's a staggering number from just one patient – but luckily, the protective power of vaccination helps reduce the actual spread by lowering the number of people susceptible to infection. Measles is extraordinarily virulent, spreading through tiny airborne particles released during coughing or sneezing. It doesn't even require direct contact. It's so infectious that an unvaccinated person can catch the virus just by entering a room where an infected person was present two hours earlier. People can also be infectious and spread the virus before they develop symptoms or have any reason to isolate. Other infectious diseases with high R0 values include pertussis, or whooping cough (12 to 17), chickenpox (ten to 12), and COVID, which varies by subtype but generally falls between eight and 12. While many patients recover fully from these conditions, they can still lead to serious complications, including pneumonia, seizures, meningitis, blindness, and, in some cases, death. Low spread, high stakes At the other end of the spectrum, a lower infectivity rate doesn't mean a disease is any less dangerous. Take tuberculosis (TB), for example, which has an R0 ranging from less than one up to four. This range varies depending on local factors like living conditions and the quality of available healthcare. Caused by the bacterium] Mycobacterium tuberculosis, TB is also airborne but spreads more slowly, usually requiring prolonged close contact with someone with the active disease. Outbreaks tend to occur among people who share living spaces – such as families, households, and in shelters or prisons. The real danger with TB lies in how difficult it is to treat. Once established, it requires a combination of four antibiotics taken over a minimum of six months. Standard antibiotics like penicillin are ineffective, and the infection can spread beyond the lungs to other parts of the body, including the brain, bones, liver and joints. What's more, cases of drug-resistant TB are on the rise, where the bacteria no longer respond to one or more of the antibiotics used in treatment. Other diseases with lower infectivity include Ebola – which is highly fatal but spreads through close physical contact with bodily fluids. Its R0 ranges from 1.5 to 2.5. Diseases with the lowest R0 values – below one – include Middle East respiratory syndrome (Mers), bird flu and leprosy. While these infections are less contagious, their severity and potential complications should not be underestimated. The threat posed by any infectious disease depends not only on how it affects the body, but also on how easily it spreads. Preventative measures like immunisation play a vital role – not just in protecting people, but also in limiting transmission to those who cannot receive some vaccinations – such as infants, pregnant women and people with severe allergies or weakened immune systems. These individuals are also more vulnerable to infection in general. This is where herd immunity becomes essential. By achieving widespread immunity within the population, we help protect people who are most susceptible. Get your news from actual experts, straight to your inbox. Sign up to our daily newsletter to receive all The Conversation UK's latest coverage of news and research, from politics and business to the arts and sciences. This article is republished from The Conversation under a Creative Commons license. Read the original article. Dan Baumgardt does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
