Covid 19 coronavirus: Why asymptomatic contacts aren't tested

*The Paihia woman and her daughter referenced in this story have chosen to go by an alias.*

Like many in Northland, Sarah* and her family are in limbo.

Two weeks ago, Sarah picked up her daughter Thalia* from Auckland Airport, who had just finished her journey home from England which brought her through Dubai with the world gripped by Covid-19.

From information on Ministry of Health's (MoH) website, as many as six individuals with Covid-19 could have been on Thalia's flight, not including the unknown number which could have passed through Dubai's airport at the same time.

The Paihia family of five has been in isolation ever since and despite nearly all experiencing various flu-like symptoms, they were told they would not be tested.

Head to the bottom of the story for Northland's testing stations

Current MoH guidelines state only people who are experiencing symptoms (fever, cough, shortness of breath or sore throat) as well as having travelled overseas in the last 14 days, working in healthcare or have been in contact with a positive case would be tested.

Sarah said if she had the option, she would get tested for peace of mind, but acknowledged she did not want to waste resources for those who needed them.

"It was all a bit of a whirlwind," she said.

"We've all been a bit not right, but not terrible and it's kind of gone through us."

Sarah's story has been one of many told anecdotally of people with little or no symptoms thinking they should be tested and being refused.

Infectious diseases doctor and University of Otago epidemiologist Ayesha Verrall empathised with those who felt a precautionary test was necessary.

However, Verrall explained that testing someone who did not fit the criteria may give them false hope.

"As of today, the definition is if you're a case contact and you've got a symptom, you can be tested,' she said.

"The test is going to perform best in someone with symptoms. If you do it on someone who doesn't have symptoms, the test might be negative and they might go on to develop symptoms later when the test would be positive."

Across Northland's seven community testing centres, 316 tests had performed between March 20-26.

Verrall said New Zealand's current concern was its ability to contact trace confirmed cases to help avoid a large outbreak, which could lead to mass casualties.

Contact tracing was the process by which medical officials notified contacts of confirmed Covid-19 cases, who had been within two metres of the infected for more than 15 minutes over the time they had been ill, and advised them to go into isolation.

Verrall said this process had been made easier by the lockdown enforced since Wednesday, but she warned if efforts weren't made to streamline the process before New Zealand came out of lockdown, the consequences could be serious.

"We should come out of lockdown with stronger contact tracing and testing capability so that we can stay at [alert] level 1 or 2 and have confidence that if we had a small number of community transmission cases, we could contact trace them and deal with it.

"[If not], the risk is going back into lockdown very readily because we don't have the confidence we can contain community spread through contact tracing."

Verrall, an expert on contact tracing, said the MoH needed the ability to contact trace 1000 cases per day. But, she had seen no evidence to suggest New Zealand could contact trace over 50 per day currently.

While she accepted it would require creative thinking, Verrall said her expectation of tracing 1000 cases daily was feasible with the help of extra resources and things such as smartphone apps.

Such apps, Verrall said, had been used in Singapore and Taiwan as a way to instantly notify a confirmed case's contacts of a positive diagnosis, advising them to isolate.

• Covid19.govt.nz: The Government's official Covid-19 advisory website

Despite the clear risk of a mass outbreak in New Zealand, Verrall said Kiwis could take solace in the prompt actions taken by the Government compared to the harder-hit countries like Italy and the United States.

Verrall said if people followed the core instructions - washing your hands, staying home while sick, not touching your face while in public - they could be confident in seeing progress soon.

"If you're sticking to the simple things that we know work, we should look forward with confidence that we can start getting parts of normal life back in New Zealand again."