In January, the committee said aged care workers should be "strongly encouraged" to get vaccinated, but given there was little data about the effectiveness of vaccines in preventing the spread of COVID-19, it stopped short of mandating the jabs.

The Victorian government said it expects all front-line aged care and health workers to be vaccinated against COVID-19. In an attempt to increase coverage, it is now allowing aged care and disability care workers to jump the queue in state-run mass vaccination clinics.

Data from places which have made influenza vaccination mandatory in the past suggests it's clear vaccine coverage will increase after a mandate.

However, before moving forward we need to make sure we have exhausted the other options. The Victorian government is making a good start by reducing the barriers to access.

To really understand whether mandates are needed, it's critical we get a good handle on the number of health and aged care workers who have received the vaccine, and whether we are getting equity in coverage across and within organisations.

It's important to remember the term "health workers" includes clinical and non-clinical staff. Tracking vaccine uptake for health workers can be challenging for a range of reasons, including that staff can receive their vaccine onsite or at other locations.

Australian hospital staff are required to show evidence they're protected from a range of vaccine preventable diseases.

The list of diseases differs slightly depending on the state or territory. In NSW, for example, front-line staff must show evidence they're vaccinated against measles, diphtheria, tetanus, pertussis (whooping cough), and varicella (chickenpox).

Annual flu vaccines are highly recommended for healthcare workers in NSW, but not required. It's currently only mandatory for those in high-risk situations, for example intensive care and oncology ward staff.

Internationally, mandates for influenza are more common in parts of the United States, while countries in Europe often require health workers to show evidence of protection from other vaccine preventable diseases.

In an attempt to support flu vaccine uptake, staff members running vaccine clinics in Australia would tell me they offered extended opening hours, had mobile clinics, offered raffles and lollipops, had education sessions with influenza experts, and used declination forms (a legal document that signals an individual's intent to refuse a recommended treatment) - but coverage remained the same. One staff member I spoke to likened it to banging her head on the wall. Nothing she did increased coverage at her hospital.

At this point, organisations or governments often shift away from voluntary programs and introduce mandatory requirements.

While vaccine requirements in Australia for influenza are still in their infancy, they have been in place in some settings in the United States for much longer and have been shown to work.

One study from the United States looked at flu vaccine uptake in healthcare workers at University of California Irvine Healthcare. It found that after introducing measures and incentives like the ones above, coverage rose from 44 per cent of staff to 62.9 per cent. But it was only after the vaccine became mandatory that coverage reached over 85 per cent.

What's more, in 2016-17, influenza vaccination was highest among US hospital workers who were required by their employer to be vaccinated (98.3 per cent). When vaccination wasn't required, promoted, or offered on-site, rates were as low as 45.8 per cent.

Multiple arguments are used to support mandatory vaccination, but the focus tends to be the obligation for staff to "do no harm" and patients' and residents' (and staff members') right to a safe environment, free from the risk of infection from a staff member. This right is both an ethical and a legal requirement.

Those who oppose mandates often draw on the rights of health workers to autonomy, question the data supporting the rationale for the mandate, or criticise the level of effect the vaccine has in reducing transmission from staff members to patients. Others suggest adding a mandate will drive staff to quit their jobs. But research shows that isn't the case.

We urgently need to reduce the chance of COVID-19 transmission in healthcare and aged care organisations to patients and staff members. But are we at that tipping point of needing to mandate a COVID-19 vaccine?

To answer that question, we need to consider the following:

When we've tried these strategies and haven't seen improved coverage, we need to accept voluntary approaches probably won't cut it. Every study on influenza vaccination of health workers points to a ceiling effect that will not be broken unless the vaccine gets mandated.

If we accept the same situation will occur for COVID-19 vaccination, mandatory policies may be the only way forward in ensuring high coverage of staff.

However, in moving forward with a mandate, it's critical we work with the health workers at the receiving end of the policy, as well as those staff members tasked with introducing and enforcing it.