Covid 19 coronavirus Delta outbreak: Ask us anything on Covid

Living in alert level 4 lockdown comes with a unique set of rules, some of which are not always clear. In our new daily feature we answer questions from readers about anything Covid-related. Email covidquestions@nzherald.co.nz

Why is the time frame listed at locations of interest limited only to when a Covid infected person was there? Advice is given to isolate, test and retest if there at the same time. Surely that is saying that the Delta variant isn't transmissable on surfaces?
If a Covid infected person has picked up the same sauce bottle within a 6-9 hour period or turned on the taps, why is that not considered a transmission risk?
We were told last year that the virus can survive on different surfaces for different periods, on some surfaces for up to a week - hence the need to be vigilant about hand sanitising/washing. The time frame given as the 'risk period' at the locations of interest, is therefore not making sense.
Susan H

Associate Professor Siouxsie Wiles says the concern around surface - or fomite - transmission dates back to the early stages of the pandemic and was based on what has now been deemed to be "old statistics".

Thanks to new studies conducted since the outbreak, scientists now had a better understanding of how droplets behaved.

"It's clear at this stage of the pandemic that the overwhelming risk is aerosols. I'm not going to rule out surface transmission but it does seem unlikely," she says.

More important was the airflow in the location, she says, citing the case of the maintenance worker who contracted Covid after using a lift in the Rydges Hotel isolation facility minutes after an infected guest.

While the buttons were originally thought to be the source of transmission, Wiles says it was now believed respiratory droplets or aerosols in the air were more likely given the confined space and lack of airflow.

Data from restaurant outbreaks showed the spread of Covid was more to do with where people were seated in terms of proximity to the infected person and the airflow in that part of the establishment, Wiles explained.

She says she's confident the times listed in the locations of interest would be pretty conservative given the focus on trying to quickly identify anyone who could potentially be spreading the virus.

Otago University epidemiologist Professor Michael Baker explained earlier this year that no cases arising from surface transmission had ever been documented.

The US Centers for Disease Control now states that fomites are "not thought to be a common way that Covid-19 spreads" - and some studies have indicated the risk is exaggerated.

All that's not to stay people should stop washing their hands regularly. As well as minimising the already low risk of picking the virus up from a surface, hand hygiene protects you from a host of other illnesses.

Just want to know if all Coromandel tests come back negative.
Angela K

So far all of the confirmed cases of Covid in the current outbreak have been in Auckland or Wellington residents.

That means no one who resides in the Coromandel has tested positive.

There may, however, have been Aucklanders who picked up the virus while visiting the Coromandel at the same time as the first community case reported - the 58-year-old Devonport tradesman who was visiting the area while infectious.

What can and can't you do for exercise in alert level four lockdown? Photo / Michael Craig

How does anyone know that the vaccine has stopped them from getting sick? Or how would anyone know they've been exposed even and the vaccine subsequently protected them?
Christa M

If we're talking about a fully vaccinated New Zealander, there's no way to know with 100 per cent certainty if the vaccine has worked for you.

If you're deemed a close contact or have been in a location of interest at the listed time and have not picked up the virus you might assume it's working.

If you're a household member of a confirmed case or have been in very close contact with an infected person and have still not tested positive then it's a good assumption the vaccine has protected you.

As for how Pfizer tested their vaccine, there have been three stages of clinical trials and plenty of monitoring as the vaccine is rolled out around the world.

The first clinical trials measured the immune response to the vaccine by looking at the level of antibodies in the bloodstream and how well they worked to neutralise the Covid 19 virus in laboratory tests.

In phase two and three the efficacy was tested in about 44,000 participants where Covid was already circulating in communities.

About half the participants received the vaccine and half received a placebo.

The trial then looked at how many people got Covid symptoms after they were vaccinated compared to how many got symptoms after getting the placebo.

Participants had two doses of the vaccine or placebo at different intervals. They were then closely monitored and evaluated for at least two months after their second dose.

The trials found that after getting two doses of the Pfizer vaccine more than nine out of 10 people were protected against Covid 19.

To understand the long-term efficacy and safety, participants in the clinical trials are being tracked for another two years.

Where do I have to wear my mask when I am outside?

At alert level 4, anyone aged 12 and over legally must wear a face covering if they are a customer or an employee involving customer contact at a business or service.

This means, you legally must wear a face covering on public transport and at departure points like bus stops or train stations; on flights; in taxi or ride-share vehicles (both drivers and passengers); when visiting healthcare facilities; and inside any essential businesses and services that are still open and involve customer contact.

You do not legally have to wear masks while walking or exercising outside although it is encouraged any time you leave home.

Can I drive my car to an exercise area? How far is my boundary?

This is a bit of a grey area where people are asked to use their own judgement and be sensible.

The Government Covid 19 website states you are able to drive to a place to exercise, like a park or beach, but you should stay close to where you live.

People are encouraged to stay within their neighbourhood or suburb.

When it comes to what type of exercise you can do, people are asked to stick to simple activities where it is unlikely you will get injured or lost. That rules out swimming, surfing, boating, hunting or tramping.

You may only exercise with those in your bubble and must keep at least 2m away from others.