Under pressure for some months to open up travel between Australia and New Zealand, our Prime Minister has rightly pointed out that the Brisbane outbreak is another reminder of the need for caution and due diligence in any change to border controls.
However, the release of a report from the Centres for Disease Control and Prevention (CDC) this week is a coincidental counter to that, and further cause for optimism.
New York epidemiologist Celine Gounder said the results were real-world evidence that the Pfizer and Moderna mRNA vaccines prevent infection, not just disease and death.
The "interim estimates of vaccine effectiveness" presented new data from tests carried out on US frontline workers who had received the Pfizer-BioNTech and Moderna vaccines at eight locations.
The report was compiled from results from prospective cohorts of 3950 healthcare personnel, first responders, and other essential and frontline workers who completed weekly Covid-19 testing for 13 consecutive weeks.
Under these "real-world conditions", the messenger RNA vaccine effectiveness of full immunisation (14 days after the second dose) was found to be 90 per cent against Covid-19 infections regardless of symptom status; and 80 per cent 14 days after the first dose but before the second dose.
The finding is a further advance on analysis from Phase III trial results and two other recent estimates of vaccine effectiveness for partial immunisation with the Pfizer-BioNTech vaccine among healthcare personnel, including an effectiveness of 72 per cent 21 days after receiving the first dose compared to laboratory-confirmed infection identified by routine testing in the United Kingdom.
The UK trial had also put vaccine effectiveness at 60 per cent by 14 days after the first dose.
The US authors of the latest CDC report said their findings conclusively show authorised mRNA Covid-19 vaccines are proven as effective for preventing Covid-19 infection in actual vaccination rollouts.
"These interim vaccine effectiveness findings for both Pfizer-BioNTech's and Moderna's mRNA vaccines in real-world conditions complement and expand upon the vaccine effectiveness estimates from other recent studies and demonstrate that current vaccination efforts are resulting in substantial preventive benefits among working-age adults.
"Covid-19 vaccination is recommended for all eligible persons," they concluded.
The news that a single dose of New Zealand's preferred Pfizer vaccine is so effective could be grist to considerations of rolling out first doses sooner and wider, rather than the one-two shot for each person that has been carried out so far.
Philadelphia Professor of Vaccination Dr Paul Offit has warned against dropping the second shot entirely however, as he said it provided "durable" protection.
Once again, science is providing an uplifting flipside to the disappointments as this pandemic runs its course.
