COVID-19: Modeller advises better testing needed to identify new variants at the border

Auckland University's Dr David Welch says we should be "sequencing pretty much anything that comes through the border".
Auckland University's Dr David Welch says we should be "sequencing pretty much anything that comes through the border". Photo credit: Getty Images

A COVID-19 modeller says with the impending reopening of the country's borders, Aotearoa is not prepared for finding "exactly what's coming into the country".

Auckland University's Dr David Welch said the border reopening had increased the need for better testing for the virus to guard against new variants.

"We'd really like to be sequencing pretty much anything that comes through the border, so anyone any other tourists or recent arrivals who take a RAT test in the first week - it's compulsory in the first week - and anyone who takes it in the first couple of weeks should really be sending that swab in to get to get sequenced by a sequencing lab," Welch told Morning Report.

A PCR testing system did not have to be the only way to go, he said.

"We could set up a system where people get a couple of swabs to take and if they test positive then they simply take a second swab and pop it in envelope and send it to their local lab and then that's when any viral material can be extracted and then sequenced."

Keeping track of variants would help to stay aware of what the country might be facing, he said.

"So far MIQ has given us a real time buffer and that time buffer has allowed us to to plan to prepare.

"If we can detect something at the border then you know it would still have to grow inside New Zealand and spread, so spotting at the border rather than once it's already spread widely, could give us a … two or four weeks heads-up."

He advised looking at a comprehensive testing policy "right across the board".

"The gold standard is probably what happens in the UK, so they have a prevalence survey where they basically send out RATs to random people, ask them to undertake those and a large proportion of those who are positive will be sequenced.

"So they're sequencing about 10 percent of all community cases. They're sequencing nearly everything that comes into a hospital or across the border.

"By contrast, we're sequencing less than 1 percent of current community cases, and we've only got about 10 to 20 percent of recent hospitalised cases.

"So we really need to ramp up this system and make it much more comprehensive and give us a much better picture of what's going on."

RNZ