People who are fully or partially vaccinated in New Zealand will still need to follow alert level 4 rules after a new community case was discovered.
At the moment, scientists are still trying to determine just how much more transmissible Delta is, but preliminary guidance indicates it could be as much as 90 per cent more infectious.
Yesterday, it was revealed that the Delta variant of Covid-19 was transmitted when doors were simultaneously open for just seconds at a quarantine facility.
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Globally, both the World Health Organisation and US Centers for Disease Control and Prevention have changed their guidance on masking as Delta has spread.
The CDC has also advised that Delta can spread among the vaccinated.
The World Health Organisation recommended at a June 25 press conference that fully vaccinated people continue to wear masks and practise other safety measures.
"People need to continue to use masks consistently, be in ventilated spaces, hand hygiene, respiratory etiquette, the physical distance, avoid crowding," WHO official Dr Mariangela Simao told reporters.
"What we're saying is once you've been fully vaccinated continue to play it safe because you could end up as part of a transmission chain," Dr Bruce Aylward said at that press conference. "You may not actually be fully protected."
The CDC updated their guidelines on July 27 recommending that even fully vaccinated people should wear a mask in most public indoor settings.
"Preliminary evidence suggests that fully vaccinated people who do become infected with the Delta variant can spread the virus to others," the CDC noted in that advice.