Increasing evidence that face masks can help save lives
While the importance of social distancing and hand washing has been consistently reinforced during the pandemic, the messaging around face coverings has been less clear cut.
In the early stages of lockdown the expert opinion was there was not enough evidence to support the use of masks but that view has shifted in recent weeks and the position is increasingly that covering the nose and mouth helps to prevent the spread of the virus.
Last month the World Health Organisation (WHO) said face coverings should be worn in public where social distancing is not possible, saying new information showed they could provide "a barrier for potentially infectious droplets".
This is a significant change and is regarded as especially relevant as we move out of lockdown and the economy begins to open up.
Essentially, we need to ensure that allowing people to leave their home to work, socialise, shop and travel does not result in a spike in cases.
As we know, a number of countries have already made masks compulsory in a range of settings while in some parts of the United States, where the virus is surging, governors are urging their use even though President Trump refuses to lead by example.
In May the Northern Ireland Executive recommended face coverings where social distancing is difficult but it is fair to say that we are not seeing widespread use, possibly because of the earlier confusion over the message.
To date mask wearing has been voluntary but that changes today when they become mandatory for passengers travelling on most bus, train and ferry services in Northern Ireland.
There will be exemptions for health reasons and for children age under 13, as well as school transport.
For many people using public transport, this is a measure that may take some getting used to but all the mitigations we are being asked to observe are aimed at reducing transmission of an infection that has claimed the lives of more than 550,000 people worldwide.
The virus is still with us, in fact the R rate has shifted upwards in Northern Ireland, so we all have a responsibility to comply with the measures that protect ourselves and protect others.