People with blood cancers who are immunocompromised are now advised to have a third primary dose of COVID-19 vaccine with an mRNA vaccine.
On 8 October the Australian Technical Advisory Group on Immunisation (ATAGI) recommended a booster third dose of vaccine as part of the primary course in individuals who are severely immunocompromised to address the risk of suboptimal or non-response to the standard 2 dose schedule.
The recommendation applies to all individuals aged ≥12 years with certain conditions or on therapies leading to severe immunocompromise.
- Active haematological malignancy
- Non-haematological malignancy with current active treatment including chemotherapy, radiotherapy, and/or hormonal therapy, but excluding immunotherapy with immune checkpoint inhibitors
- Solid organ transplant with immunosuppressive therapy
- Haematopoietic stem cell transplant (HSCT) recipients or chimeric antigen receptor T-cell (CAR-T) therapy within 2 years of transplantation.
- Immunosuppressive therapies including:
- High dose corticosteroid treatment equivalent to >20mg/day of prednisone for ≥14 days in a month, or pulse corticosteroid therapy.
- Multiple immunosuppressants where the cumulative effect is considered to be severely immunosuppressive.
- Biologic and targeted therapies anticipated to reduce the immune response to COVID-19 vaccine:
- including B cell depleting agents (e.g. anti-CD20 monoclonal antibodies, BTK inhibitors, fingolimod), anti-CD52 monoclonal antibodies (alemtuzumab), anti-complement antibodies (e.g. eculizumab), anti-thymocyte globulin (ATG) and abatacept
- excluding agents with likely minimal effect on vaccine response such as immune checkpoint inhibitors, anti-integrins, anti-TNF-α, anti-IL1, anti-IL6, anti-IL17, anti-IL4 and anti-IL23 antibodies
- Selected conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDS):
- including mycophenolate, methotrexate (>0.4 mg/kg/week), leflunomide, azathioprine (>3mg/kg/day), 6-mercaptopurine (>1.5 mg/kg/day), alkylating agents (e.g. cyclophosphamide, chlorambucil), and systemic calcineurin inhibitors (e.g. cyclosporin, tacrolimus)
- excluding hydroxychloroquine or sulfasalazine when used as monotherapy
Federal Chief Medical Officer Paul Kelly said the recommendation was to go for one of the mRNA vaccines as the booster.
“The preference is to go for a third dose of the one you had first. So if you’ve had two Pfizer, the third one would be Pfizer. No one’s had two Modernas yet, so it would be likely be Pfizer. But if Pfizer is not available or unable to be taken, Moderna would be substituted,” he said.
“In certain circumstances, there may be a need to actually use AstraZeneca, for example, with some of the side effects of the second dose of an mRNA vaccine that would not be recommended to get a third one if that was the case. So there is flexibility. But the general principle is mRNA vaccine as the third dose.
According to ATAGI, the recommended interval for the 3rd dose is two to six months after the second dose of vaccine. A minimum interval of four weeks may be considered in exceptional circumstances (e.g., anticipated intensification of immunosuppression, outbreaks). People who have had a second dose more than 6 months ago should receive a 3rd dose whenever feasible.
ATAGI also advises that antibody testing is not recommended to assess for immunity to SARS-CoV-2 following COVID-19 vaccination, including in immunocompromised individuals after a 2nd or 3rd dose, because there are no serological assays that provide a definitive correlate of immunity to SARS-CoV-2.
Professor Eva Segelov is a Professor of Oncology at Monash University welcomed the recommendation “as evidence shows patients with significant immunosuppression mount a poorer response to vaccines and the response is of a shorter duration. Age and other factors also affect this.
“Many countries have adopted the third (booster) dose for immunosuppressed people and it is important and timely that Australia has done this also,” she said.