The Therapeutic Goods Administration (TGA) has approved a vaccine against respiratory syncytial virus (RSV) in Australia for the first time. The shot, called Arexvy and manufactured by GSK, will be available by prescription to adults over 60.

RSV is a contagious respiratory virus which causes an illness similar to influenza, most notably in babies and older adults.

So while it will be good to have an RSV vaccine available for older people, where is protection up to for the youngest children?

A bit about RSV

RSV was discovered in chimpanzees with respiratory illness in 1956, and was soon found to be a common cause of illness in humans.

There are two key groups of people we would like to protect from RSV: babies (up to about one year old) and people older than 60.

Babies tend to fill up hospitals during the RSV season in late spring and winter in large numbers, but severe infection requiring admission to intensive care is less common.

In babies and younger children, RSV generally causes a wheezing asthma-like illness (bronchiolitis), but can also cause pneumonia and croup.

Although there are far fewer hospital admissions among older people, they can develop severe disease and die from an infection.

RSV vaccines for older people

For older adults, there are actually several RSV vaccines in the pipeline. The recent Australian TGA approval of Arexvy is likely to be the first of several, with other vaccines from Pfizer and Moderna currently in development.

The GSK and Pfizer RSV vaccines are similar. They both contain a small component of the virus, called the pre-fusion protein, that the immune system can recognise.

Both vaccines have been shown to reduce illness from RSV by more than 80% in the first season after vaccination.

In older adults, side effects following Arexvy appear to be similar to other vaccines, with a sore arm and generalised aches and fatigue frequently reported.

Unlike influenza vaccines which are given each year, it is anticipated the RSV vaccine would be a one-off dose, at least at this stage.

Protecting young children from RSV

Younger babies don’t tend to respond well to some vaccines due to their immature immune system. To prevent other diseases, this can be overcome by giving multiple vaccine doses over time. But the highest risk group for RSV are those in the first few months of life.

To protect this youngest age group from the virus, there are two potential strategies available instead of vaccinating the child directly.

The first is to give a vaccine to the mother and rely on the protective antibodies passing to the infant through the placenta. This is similar to how we protect babies by vaccinating pregnant women against influenza and pertussis (whooping cough).

The second is to give antibodies directly to the baby as an injection. With both these strategies, the protection provided is only temporary as antibodies wane over time, but this is sufficient to protect infants through their highest risk period.

Abrysvo, the Pfizer RSV vaccine, has been trialled in pregnant women. In clinical trials, this vaccine has been shown to reduce illness in infants for up to six months. It has been approved in pregnant women in the United States, but is not yet approved in Australia.

An antibody product called palivizumab has been available for many years, but is only partially effective and extremely expensive, so has only been given to a small number of children at very high risk.

A newer antibody product, nirsevimab, has been shown to be effective in reducing infections and hospitalisations in infants. It was approved by the TGA in November, but it isn’t yet clear how this would be accessed in Australia.

What now?

RSV, like influenza, is a major cause of respiratory illness, and the development of effective vaccines represents a major advance.

While the approval of the first vaccine for older people is an important step, many details are yet to be made available, including the cost and the timing of availability. GSK has indicated its vaccine should be available soon. While the vaccine will initially only be available on private prescription (with the costs paid by the consumer), GSK has applied for it to be made free under the National Immunisation Program.

In the near future, we expect to hear further news about the other vaccines and antibodies to protect those at higher risk from RSV disease, including young children.

Allen Cheng, Professor of Infectious Diseases, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Each year, more and more Victorians become sick with a flesh-eating bacteria known as Buruli ulcer. Last year, 363 people presented with the infection, the highest number since 2004.

But it has been unclear exactly how it spreads, until now. New research shows mosquitoes are infected from biting possums that carry the bacteria. Mozzies spread it to humans through their bite.

What is Buruli ulcer?

Buruli ulcer, also known as Bairnsdale ulcer, is a skin infection caused by the bacterium Mycobacterium ulcerans.

It starts off like a small mosquito bite and over many months, slowly develops into an ulcer, with extensive destruction of the underlying tissue.

While often painless initially, the infection can become very serious. If left untreated, the ulcer can continue to enlarge. This is where it gets its “flesh-eating” name.

Thankfully, it’s treatable. A six to eight week course of specific antibiotics is an effective treatment, sometimes supported with surgery to remove the infected tissue.

Where can you catch it?

The World Health Organization considers Buruli ulcer a neglected tropical skin disease. Cases have been reported across 33 countries, primarily in west and central Africa.

However, since the early 2000s, Buruli ulcer has also been increasingly recorded in coastal Victoria, including suburbs around Melbourne and Geelong.

Scientists have long known Australian native possums were partly responsible for its spread, and suspected mosquitoes also played a role in the increase in cases. New research confirms this.

Our efforts to ‘beat Buruli’

Confirming the role of insects in outbreaks of an infectious disease is achieved by building up corroborating, independent evidence.

In this new research, published in Nature Microbiology, the team (including co-authors Tim Stinear, Stacey Lynch and Peter Mee) conducted extensive surveys across a 350 km² area of Victoria.

We collected mosquitoes and analysed the specimens to determine whether they were carrying the pathogen, and links to infected possums and people. It was like contact tracing for mosquitoes.

Molecular testing of the mosquito specimens showed that of the two most abundant mosquito species, only Aedes notoscriptus (a widespread species commonly known as the Australian backyard mosquito) was positive for Mycobacterium ulcerans.

We then used genomic tests to show the bacteria found on these mosquitoes matched the bacteria in possum poo and humans with Buruli ulcer.

We further analysed mosquito specimens that contained blood to show Aedes notoscriptus was feeding on both possums and humans.

To then link everything together, geospatial analysis revealed the areas where human Buruli ulcer cases occur overlap with areas where both mosquitoes and possums that harbour Mycobacterium ulcerans are active.

Stop its spread by stopping mozzies breeding

The mosquito in this study primarily responsible for the bacteria’s spread is Aedes notoscriptus, a mosquito that lays its eggs around water in containers in backyard habitats.

Controlling “backyard” mosquitoes is a critical part of reducing the risk of many global mosquito-borne disease, especially dengue and now Buruli ulcer.

You can reduce places where water collects after rainfall, such as potted plant saucers, blocked gutters and drains, unscreened rainwater tanks, and a wide range of plastic buckets and other containers. These should all be either emptied at least weekly or, better yet, thrown away or placed under cover.

There is a role for insecticides too. While residual insecticides applied to surfaces around the house and garden will reduce mosquito populations, they can also impact other, beneficial, insects. Judicious use of such sprays is recommended. But there are ecological safe insecticides that can be applied to water-filled containers (such as ornamental ponds, fountains, stormwater pits and so on).

Recent research also indicates new mosquito-control approaches that use mosquitoes themselves to spread insecticides may soon be available.

How to protect yourself from bites

The first line of defence will remain personal protection measures against mosquito bites.

Covering up with loose fitted long sleeved shirts, long pants, and covered shoes will provide physical protection from mosquitoes.

Applying topical insect repellent to all exposed areas of skin has been proven to provide safe and effective protection from mosquito bites. Repellents should include diethytolumide (DEET), picaridin or oil of lemon eucalyptus.

While the rise in Buruli ulcer is a significant health concern, so too are many other mosquito-borne diseases. The steps to avoid mosquito bites and exposure to Mycobacteriam ulcerans will also protect against viruses such as Ross River, Barmah Forest, Japanese encephalitis, and Murray Valley encephalitis.

Cameron Webb, Clinical Associate Professor and Principal Hospital Scientist, University of Sydney; Peter Mee, Adjunct Associate Lecturer, School of Applied Systems Biology, La Trobe University; Stacey Lynch, Team Leader- Mammalian infection disease research, CSIRO, and Tim Stinear, Professor of Microbiology, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.