Overview
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Respiratory syncytial virus (RSV) is a common cause of respiratory illness in infants and young children, as well as older adults. Each season, RSV causes substantial morbidity and mortality in older adults, including lower respiratory tract disease, hospitalisation, and death.
Arexvy is a recombinant protein vaccine that causes the immune system to produce RSV antibodies. It includes an adjuvant which is a component that enhances the immune response to the vaccination.
Arexvy is currently approved as a single dose to protect against symptomatic lower respiratory tract disease caused by RSV in adults aged 60 years and older and for adults 50 to 59 years of age who are at increased risk for RSV disease.
The risk of severe RSV among adults increases with age, with the highest rates of hospitalisation among those aged 75 years and older.
As well as older age, other risk factors include chronic medical conditions including: respiratory, cardiovascular, neurological or neuromuscular conditions (causing impaired airway clearance or respiratory muscle weakness), haematological conditions, diabetes with complications, chronic liver or kidney disorders, severe obesity (BMI ≥40 kg/m2) and moderate or severe immunocompromise. The risk is particularly increased in those with two or more chronic conditions.
Other risk groups include people who are frail, people living in nursing homes or other long-term care facilities and older people of Māori and Pacific ethnicity, especially if living in areas of high deprivation.
It is anticipated that adults may need additional doses of RSV vaccine in the future, but ideal revaccination timing is not yet known. Data to date shows protection from a single dose can last for up to three years.
Responses to vaccine
Headache
Muscle and joint pain
Injection site pain
Fatigue
Nausea
Hypersensitivity (e.g. rash)
Other formulations and brands
Palivizumab (Synagis) is a preventative RSV monoclonal antibody available to high-risk infants and young children under 24 months. It is given monthly and is funded. For more information, including eligibility criteria, see the Starship Guidelines
Nirsevimab (Beyfortus) is an injectable monoclonal antibody that prevents severe RSV in infants and young children. This is not currently approved for use in New Zealand.
Abrysvo RSV vaccine is used for the prevention of lower respiratory tract infection caused by RSV in individuals 60 years and older. It is also used in pregnant individuals at 32 through to 36 weeks gestational age for the prevention of LRTD caused by RSV in infants from birth through to six months of age. This is not currently approved for use in New Zealand.
Schedule and administration
Arexvy is indicated for active immunisation for the prevention of lower respiratory tract disease (LRTD) caused by respiratory syncytial virus RSV-A and RSV-B subtypes in adults 60 years of age and older and for adults 50 to 59 years of age who are at increased risk for RSV disease.
Arexvy is administered as a single dose of 0.5mL as an IM injection into the deltoid. The need for revaccination has not been established, but evidence shows protection for at least two RSV seasons.
It is a private market vaccine and can be ordered through HCL.
Vaccine preparation
Arexvy must be reconstituted prior to administration.
1. Withdraw the entire contents of the vial containing the adjuvant suspension into a syringe
2. Add the entire contents of the syringe into the vial containing the powdered antigen
3. Gently swirl until the powder is completely dissolved.
The reconstituted vaccine is an opalescent, colourless-to-pale brownish liquid. The reconstituted vaccine should be inspected visually for any foreign particulate matter and/or variation of appearance. If either is observed, do not administer the vaccine.
Before administration:
1. Withdraw 0.5mL of the reconstituted vaccine into the syringe
2. Change the needle so that you are using a new needle
3. Administer the vaccine intramuscularly.
Concomitant administration with Arexvy
Arexvy can be administered concurrently with other vaccines, including all National Immunisation Schedule vaccines, such as 23PPV and Tdap. Separate syringes and different injection sites should be used.
Arexvy can also be administered at the same time as Fluad Quad, another adjuvanted vaccine. Consumers should be made aware of the potential for a stronger post-vaccination response when two or more adjuvanted vaccines are administered at the same time.
There is data to support the co-administration of Shingrix and Arexvy, both of which contain the same adjuvant. Studies showed no differences in immunogenicity when administered together. Note that mild to moderate reactions can occur more frequently with co-administration, but these are short lived.
Vaccine Safety
The adjuvanted Arexvy vaccine has demonstrated good safety profiles in older adults during phase 2 and 3 clinical trials. Reactogenicity is mild to moderate with onset from 1-4 days after vaccination and generally lasting for 1 or 2 days.
Arexvy may cause some temporary reactions. These include soreness, redness or swelling at the injection site, fatigue, fever, headache, nausea, diarrhoea and muscle or joint pain. Among people aged ≥60 years who received Arexvy, 9% reported to the V-safe monitoring programme that they could not complete normal daily activities, while 0.5% saw a health care professional.
Arexvy is contraindicated in anyone with a history of a severe allergic reaction (e.g., anaphylaxis) to any component of this vaccine.
Immunocompromised people, including those receiving immunosuppressive therapy, may have a reduced immune response to Arexvy.
Real world monitoring suggests an increased risk of GBS following Arexvy although uncertainty remains regarding the magnitude of risk. As of October 2024, an FDA analysis found 7 excess cases per 1million doses of Arexvy. Patients should be warned of this possible but rare risk and encouraged to seek medical attention if they develop suggestive symptoms, such as leg weakness, tingling in limbs, incoordination or trouble with facial movements, as early medical care can reduce severity and improve outcomes.
Vaccine Effectiveness
A single dose of Arexvy is highly effective at preventing serious respiratory illness from RSV for at least two seasons (around 80% effective). This was shown in a large study (phase 3 RCT) with a follow-up of 18 months, to date.
In the first season, the vaccine reduced confirmed RSV lower respiratory tract infection by 82.6% (96.95% CI 57.9-94.1) compared to a placebo group (7 cases in vaccinated vs 40 in placebo).
It was even more effective against severe RSV illness, with a 94% reduction (1 case vs 17) (97.5% CI 62.4-99.9).
This protection held strong for people aged over 70 (VE of 84.4 percent; 95% CI 46.9-97.0) and those with at least one underlying health condition (VE of 81 percent, 95% CI 58.9-92.3).
The study also found that getting a second dose a year later offered little additional benefit compared to just one dose for two seasons.
While Arexvy provides good protection for two seasons (74.5%; 60.0-84.5% against RSV-associated lower respiratory tract disease), researchers are continuing to study optimal revaccination timing.
References
