Does a major change to a COVID-19 vaccine program alter vaccine intention? A qualitative investigation.

Background: On 8th April 2021, the Australian Technical Advisory Group on Immunisation (ATAGI) made the Pfizer-BioNtech (Comirnaty) vaccine the "preferred" vaccine for adults in Australia aged < 50 years due to a risk of thrombosis with thrombocytopenia syndrome (TTS) following AstraZeneca vaccination. We sought to understand whether this impacted COVID-19 vaccine intentions.

Method: We undertook qualitative interviews from February - April 2021 before and after the program change with 28 adults in Perth, Western Australia. Using our COVID-19 vaccine intentions model, we assessed changes in participants' COVID-19 vaccine intention before and after the program change. Participants were classified as 1) 'acceptors': no concerns about COVID-19 vaccine safety, efficacy, access and would accept whatever vaccine is offered, 2) 'cautious acceptors': some concerns and would prefer a particular vaccine brand but would accept whatever is offered, 3) 'Wait awhile': for more data, easier access, for another vaccine brand, a greater perceived COVID-19 threat or until mandatory, or 4) 'refuser': no intention to vaccinate due to concerns about safety and/or efficacy.

Results: Before the change, 7/18 of those aged < 50 years were 'acceptors,' 10/18 were 'cautious acceptors' and 1/18 was 'wait awhile.' Overall, 14/18 participants had the same COVID-19 vaccine intention after the change; 4/18 became more concerned. For those aged ≥ 50 years and before the change, 5/10 were 'acceptors' and 5/10 were 'cautious acceptors.' After the change, 8/10 still had the same COVID-19 vaccine intention; 2/10 became more cautious. The major concern before the program change was COVID-19 vaccines having different vaccine efficacy; the concern pivoted to safety.

Conclusion: The majority of participants were 'cautious acceptors' who intended on being vaccinated; many had this intention before and after the program change. The Australian government, health care providers and media need to better address COVID-19 vaccine concerns to assist those with COVID-19 vaccine intentions receive a vaccine.