Lockdown for delta, expert says

New Zealanders will have to accept the risk of going back into lockdown before the year is up with the delta variant looming, an expert says.

Aotearoa has enjoyed a Covid-free existence for months, and has so far been spared an outbreak of the highly infectious delta strain, which has spread to more than 132 countries.

This week, Covid-19 Response Minister Chris Hipkins warned delta has ‘‘materially changed’’ the risk of the virus. Contact tracing alone is ‘‘unable to get ahead’’ of the variant and restrictions are ‘‘absolutely necessary to stamp it out’’, he said.

The warning comes as there have been two separate personal protective equipment (PPE) breaches involving Covid-positive patients in Auckland in the space of just one week.

University of Auckland Professor Shaun Hendy, a Covid-19 modeller, said that at the point delta was discovered there could already be ‘‘several hundred’’ potential cases because of increased infectivity – creating a ‘‘massive challenge’’ for contact tracers.

When a Covid-positive traveller from Sydney spent a weekend in Wellington, less than 20 per cent of

the 2600 people potentially exposed could be traced. ‘‘By the time you figure out you’ve got a problem, the chances are it’s too big to deal with [through contact tracing] alone,’’ Hendy said. This puts the emphasis back on having to use lockdown, particularly given our current vaccination coverage.

New Zealand has about 15 per cent vaccination coverage. While this ‘‘certainly starts to help’’, it is unlikely to ‘‘change the game’’ until about 50 per cent of people are vaccinated, Hendy said. Until the country reaches that level of coverage ‘‘we would need to be thinking about alert level 4’’ in case delta cropped up in the community.