New strains’ potential prompts warning

AUCKLAND: A Level 4 lockdown longer than that back in March would be needed to stamp out new strains of Covid19 which had the ‘‘potential for explosive, exponential growth’’ if they entered the community, scientists say.

The warning comes as iwi leaders join calls for New Zealand to tighten up on the number of people arriving into the country, particularly from areas where the new strains are rife.

On Monday it was reported there were already 19 cases of the United Kingdom strain detected in New Zealand since December 13 and one case of the South African variant.

Prof Michael Plank, of Te Punaha Matatini and the University of Canterbury, warned about the new variant called B117, which has exploded across the UK, and the similar variant found in South Africa.

‘‘This is a serious concern because of the potential for explosive, exponential growth.’’

Prof Plank said the higher infection rate raised the risk of the B117 variant leaking through our border because there was a greater chance of a quarantine worker getting infected.

Consequently, if there was a community outbreak, it would spread much faster and lead to much bigger outbreaks because it was compounded by exponential growth.

For example, the original strain of Covid19 would typically infect about 160 cases after five links in the chain, whereas the new variant would typically infect about 1000 cases in the same time.

Prof Plank said if there was a community outbreak, there could need to be stricter restrictions to bring it under control.

‘‘Alert Level 3 was effective in containing the August outbreak, but it's likely we would need to use Level 4 to have the same effect on the new variant.

‘‘And restrictions might need to be in place for longer to eliminate the virus.’’

Prof Plank said the Government's recently announced additional day zero test on arrival and a preflight test for people departing from the United States or the UK were good ideas.

He said it would be sensible to extend these requirements to all arrivals as the strain was spreading around the world rapidly.

A period of pretravel quarantine would also help to reduce the number of cases arriving at the border, he said.

While there was no evidence existing vaccines were any less effective against the new strain, a higher proportion of New Zealanders would need to be vaccinated to achieve immunity due to the increased transmission rate.

On Sunday, University of Otago epidemiologist Prof Michael Baker said other measures to restrict the chances of an outbreak of the new strain could involve a ‘‘traffic light system’’ for travel.

Countries with no or low community transmission could be green, while places like the UK and parts of the US would be red, meaning flights from there would be suspended.

Canada had banned flights from the UK since December 21 to keep out the new strain.

France, Germany, Italy, the Netherlands, Belgium, Austria, Ireland and Bulgaria all announced restrictions on UK travel.

In response to the new strain, the Iwi Chairs Forum Pandemic Response Group has issued a range of priorities to protect vulnerable groups of people.

Various studies have found Maori would be disproportionately affected by Covid19 if there was a large outbreak here, largely due to preexisting health inequities.

The latest research found Maori and Pacific people were more than twice as likely to be hospitalised for Covid19, findings that prompted a call to officials prioritising vaccine shots.

Dr Rawiri Taonui, who conducted research for the forum, called for more urgency in the government response, including applying the predeparture negative test to all travellers as soon as possible, and bringing the vaccination introduction forward to February.

Due to the disproportionate effects on Maori, the ‘‘atrisk’’ age for Maori should be lowered to 50, Dr Taonui said.

He also said the Government needed to consider capping arrivals at 300 per day, down from about 400 at present, and when the number of active cases in MIQ reached 20 to 30 cases, cap the number of entries to a lower level.

‘‘With the threat from new strains the number of arrivals into New Zealand is no longer sustainable.’’ — The New Zealand Herald