The spread of infection among a household may come down to opening windows and allowing a case to isolate in a separate room, according to one Covid-19 expert.
University of Auckland senior lecturer Dr David Welch believes there is a good chance some people could avoid infection with the Omicron variant.
One study based in the UK showed if a person were to get infected there was a 15 per cent chance that others would get infected in the following week. However, Welch also mentioned a similar Danish study that found a 50 per cent chance.
"It's somewhere in that range you know 15 to 50 per cent but it means basically you've got a greater chance of getting infected if you are sharing a household with someone who's a case."
Opening windows for ventilation and having a designated isolation room will help stop the spread of infection, he said.
But, Welch acknowledged this can be hard for households across the country.
"We don't do housing very well in New Zealand and overcrowded housing across the country and poorly ventilated housing has been a major health issue for all sort of diseases and we have been studying this since the nineties."
Currently, all household members must isolate a minimum of seven days, they must also get tested on day 3, day 7 and when they develop symptoms.
While some households may not be able to avoid infection, Welch said small things like getting a booster shot and basic hygiene can also help stop the spread of infection.
On Monday, the Ministry of Health said the importance of getting boosted cannot be underestimated.
"Getting vaccinated and boosted will help reduce your risk of severe Covid-19 illness and could save your life," the ministry said.
"Getting boosted will not only reduce your risk of severe illness, but it will also help to protect our most vulnerable communities."
Generally, in Covid cases, Welch said it is rare to see a person infected with many varions or viral particles which set off an infection.
"It's usually one, two or maybe three so even when people have high exposure, they're in a room for a long time with someone whose infected they still only seem to get initially infected by one or two particles," Welch said.
"That means it doesn't seem to be a big difference in outcomes of the disease whether you have a high initial exposure or a low initial exposure."
However, he said there is a higher chance of infection if a person is faced with high exposure.
"There are a lot of good reasons to avoid a high exposure in the first place if possible."