Updated COVID-19 Vaccine Recommendations

While COVID-19 may no longer be considered a public health emergency, it continues to have a significant impact on health services and the community. Residential aged care homes (RACH) continue to experience outbreaks. As of 11 April 2024, there were 209 active outbreaks in RACHs across the country. Outbreaks are highest in New South Wales and Victoria, with these states recording 29 and 27 new outbreaks in the previous seven days, respectively. In Australia, over 100,000 infections have already been reported this year. However, given the reduced volume of testing, this figure likely underestimates the actual number of cases.

Over 70.7 million COVID-19 vaccine doses have been administered in Australia since the vaccination program began in early 2021. Vaccination remains the most important measure to protect people at risk of severe disease. However, only 22.9% of people aged 65-74 and 38.1% of those over 75 have received a booster in the last six months.

The Australian Technical Advisory Group on Immunisation (ATAGI) has recently updated its advice on the use of COVID-19 vaccines. This advice contains important information regarding:

• Recommendations for additional doses of COVID-19 vaccine;
• Timing of vaccination; and
• The preferred COVID-19 vaccines for various age groups.

Table 1 provides an overview of the COVID-19 vaccines used in Australia.

Table 1. COVID-19 vaccines registered in Australia (adapted from ATAGI 2024)

*Not yet available

The Omicron XBB.1.5 vaccines are currently preferred as they provide a better immune response against Omicron variants. Early data suggests that these newer vaccines are as well tolerated as the original and bivalent formulations of Spikevax® and Comirnaty®. In the three days after receiving an XBB.1.5 COVID-19 vaccine, no adverse effects were reported for 73% of Comirnaty® recipients and 54% of Spikevax® recipients. For each XBB.1.5 vaccine, local reactions were the most common adverse effects, followed by fatigue, muscle or joint pain, and headache. The rate of reported medical attendance following vaccination with Comirnaty® XBB.1.5 and Spikevax® XBB.1.5 was low at 0.3% and 0.4%, respectively. The AusVax Safety website provides additional safety data for each vaccine.

An Omicron XBB.1.5 vaccine is not yet available for infants and children under five years of age. However, Comirnaty® Omicron XBB.1.5 (6 months – 5 years formulation) has been approved by the Therapeutic Goods Administration (TGA). Once this product is available, it will be the preferred vaccine for this age group. Until then, the age-appropriate original Comirnaty® vaccine should be used in this population, where indicated.

Vaccine timing:

A primary vaccination course is recommended for all adults 18 years of age or older, and from six months of age for children with risk factors for severe disease or death from COVID-19. A primary course is now considered one dose for most people. However, for people with severe immunocompromise, a primary course is two or three doses.

The current ATAGI recommendations for the administration of additional COVID-19 vaccine doses include:

• Every six months for adults ≥ 75 years;
• Every 12 months (with consideration of six-monthly dosing) for adults aged 65-74 years;
• Every 12 months (with consideration of six-monthly dosing) for adults aged 18-64 years with severe immunocompromise;
• Consideration of an annual dose for all other adults; and
• Consideration of an annual dose for children aged 5 to <18 years with severe immunocompromise.

Examples of severe immunocompromise for which additional doses of COVID-19 vaccine may be required can be found in the Australian Immunisation Handbook. These include:

• Haematological malignancies (treated and untreated);
• Malignancy, solid organ transplantation, autoimmune and inflammatory conditions currently treated with therapies such as conventional chemotherapy, significant doses of conventional immunosuppressants, and some monoclonal antibodies;
• HIV with a CD4+ cell count below 200;
• Primary immunodeficiency (e.g. complement defects); and
• Chronic kidney disease requiring dialysis.

The recommended timing of additional vaccine doses is summarised in Table 2. Where it is stated that additional doses may be considered, this should include an individual risk-benefit assessment.

Table 2. Recommended timing of COVID-19 vaccine doses following primary course (adapted from ATAGI 2024)

ATAGI advises that COVID-19 vaccines may be administered at the same time as any other vaccine for people five years of age or older.

Treatment:

Most cases of COVID-19 are mild and can be managed symptomatically at home. Specific antiviral treatments are available for higher-risk groups.

Two oral treatments for COVID-19 are available: Lagevrio® (molnupiravir) and Paxlovid® (nirmatrelvir and ritonavir). From 1 March 2024, the Pharmaceutical Benefits Scheme (PBS) eligibility criteria were modified for these therapies. People who test positive for COVID-19 may now be eligible for PBS-subsidised therapies if they meet the following criteria:

• Are 70 years of age or older (regardless of risk factors and presence of symptoms);
• Are 50 years of age or older and have two additional risk factors for developing severe disease;
• Are a First Nations person aged 30 years or older with one additional risk factor for developing severe disease; or
• Are 18 years of age or older and moderately to severely immunocompromised or have previously been hospitalised for COVID-19.

For the purpose of PBS eligibility, risk factors include:

• Residing in an aged care facility;
• Living with disability with multiple conditions and/or frailty;
• Neurological conditions (e.g. stroke, dementia) and demyelinating conditions (e.g. multiple sclerosis);
• Chronic respiratory conditions (e.g. COPD, moderate or severe asthma);
• Obesity or diabetes (type I or II requiring medication);
• Heart failure, coronary artery disease, cardiomyopathies;
• Kidney failure or cirrhosis; and
• Living remotely with reduced access to higher level healthcare.

Paxlovid® remains the preferred oral antiviral for COVID-19. Current evidence suggests that it is superior to Lagevrio® in terms of hospitalisation and mortality rates. However, Paxlovid® is contraindicated in severe renal or hepatic impairment and with some medications that are highly dependent on CYP3A for clearance. Lagevrio® is only PBS-subsidised when Paxlovid® is contraindicated.

Summary

The recommendations for COVID-19 vaccination have recently been updated. Some of the more significant points include the preference for the Omicron XBB.1.5 vaccines and changes to the definition of a primary dose. Vaccination continues to be an important measure to reduce the risk of severe disease and death from COVID-19.