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.

Allergies happen when your immune system overreacts to a normally harmless substance like dust or pollen. Hay fever, hives and anaphylaxis are all types of allergic reactions.

Many of those affected reach quickly for antihistamines to treat mild to moderate allergies (though adrenaline, not antihistamines, should always be used to treat anaphylaxis).

If you’re using oral antihistamines very often, you might have wondered if it’s OK to keep relying on antihistamines to control symptoms of allergies. The good news is there’s no research evidence to suggest regular, long-term use of modern antihistamines is a problem.

But while they’re good at targeting the early symptoms of a mild to moderate allergic reaction (sneezing, for example), oral antihistamines aren’t as effective as steroid nose sprays for managing hay fever. This is because nasal steroid sprays target the underlying inflammation of hay fever, not just the symptoms.

Here are the top six antihistamines myths – busted.

Myth 1. Oral antihistamines are the best way to control hay fever symptoms

Wrong. In fact, the recommended first line medical treatment for most patients with moderate to severe hay fever is intranasal steroids. This might include steroid nose sprays (ask your doctor or pharmacist if you’d like to know more).

Studies have shown intranasal steroids relieve hay fever symptoms better than antihistamine tablets or syrups.

To be effective, nasal steroids need to be used regularly, and importantly, with the correct technique.

In Australia, you can buy intranasal steroids without a doctor’s script at your pharmacy. They work well to relieve a blocked nose and itchy, watery eyes, as well as improve chronic nasal blockage (however, antihistamine tablets or syrups do not improve chronic nasal blockage).

Some newer nose sprays contain both steroids and antihistamines. These can provide more rapid and comprehensive relief from hay fever symptoms than just oral antihistamines or intranasal steroids alone. But patients need to keep using them regularly for between two and four weeks to yield the maximum effect.

For people with seasonal allergic rhinitis (hayfever), it may be best to start using intranasal steroids a few weeks before the pollen season in your regions hits. Taking an antihistamine tablet as well can help.

Antihistamine eye drops work better than oral antihistamines to relieve acutely itchy eyes (allergic conjunctivitis).

Myth 2. My body will ‘get used to’ antihistamines

Some believe this myth so strongly they may switch antihistamines. But there’s no scientific reason to swap antihistamines if the one you’re using is working for you. Studies show antihistamines continue to work even after six months of sustained use.

Myth 3. Long-term antihistamine use is dangerous

There are two main types of antihistamines – first-generation and second-generation.

First-generation antihistamines, such as chlorphenamine or promethazine, are short-acting. Side effects include drowsiness, dry mouth and blurred vision. You shouldn’t drive or operate machinery if you are taking them, or mix them with alcohol or other medications.

Most doctors no longer recommend first-generation antihistamines. The risks outweigh the benefits.

The newer second-generation antihistamines, such as cetirizine, fexofenadine, or loratadine, have been extensively studied in clinical trials. They are generally non-sedating and have very few side effects. Interactions with other medications appear to be uncommon and they don’t interact badly with alcohol. They are longer acting, so can be taken once a day.

Although rare, some side effects (such as photosensitivity or stomach upset) can happen. At higher doses, cetirizine can make some people feel drowsy. However, research conducted over a period of six months showed taking second-generation antihistamines is safe and effective. Talk to your doctor or pharmacist if you’re concerned.

Myth 4. Antihistamines aren’t safe for children or pregnant people

As long as it’s the second-generation antihistamine, it’s fine. You can buy child versions of second-generation antihistamines as syrups for kids under 12.

Though still used, some studies have shown certain first-generation antihistamines can impair childrens’ ability to learn and retain information.

Studies on second-generation antihistamines for children have found them to be safer and better than the first-generation drugs. They may even improve academic performance (perhaps by allowing kids who would otherwise be distracted by their allergy symptoms to focus). There’s no good evidence they stop working in children, even after long-term use.

For all these reasons, doctors say it’s better for children to use second-generation than first-generation antihistimines.

What about using antihistimines while you’re pregnant? One meta analysis of combined study data including over 200,000 women found no increase in fetal abnormalities.

Many doctors recommend the second-generation antihistamines loratadine or cetirizine for pregnant people. They have not been associated with any adverse pregnancy outcomes. Both can be used during breastfeeding, too.

Myth 5. It is unsafe to use higher than the recommended dose of antihistamines

Higher than standard doses of antihistamines can be safely used over extended periods of time for adults, if required.

But speak to your doctor first. These higher doses are generally recommended for a skin condition called chronic urticaria (a kind of chronic hives).

Myth 6. You can use antihistamines instead of adrenaline for anaphylaxis

No. Adrenaline (delivered via an epipen, for example) is always the first choice. Antihistamines don’t work fast enough, nor address all the problems caused by anaphylaxis.

Antihistamines may be used later on to calm any hives and itching, once the very serious and acute phase of anaphylaxis has been resolved.

In general, oral antihistamines are not the best treatment to control hay fever – you’re better off with steroid nose sprays. That said, second-generation oral antihistamines can be used to treat mild to moderate allergy symptoms safely on a regular basis over the long term.

Janet Davies, Respiratory Allergy Stream Co-chair, National Allergy Centre of Excellence; Professor and Head, Allergy Research Group, Queensland University of Technology; Connie Katelaris, Professor of Immunology and Allergy, Western Sydney University, and Joy Lee, Respiratory Allergy Stream member, National Allergy Centre of Excellence; Associate Professor, School of Public Health and Preventive Medicine, Monash University

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