The proportion of Delta cases has significantly reduced over time and evidence suggests that Delta does not currently pose a significant risk to public health. The Delta variant has not been detected in Aotearoa New Zealand since 2 March 2022. Once the Omicron variant arrived in New Zealand it replaced Delta as the predominant variant. Read the about the Delta Response Rapid Review. In October 2021, the Director-General of Health commissioned an independent review into the MinistryвЂ™s response to the August 2021 Delta outbreak. The nature of Delta created a significant challenge in New Zealand and required a whole of system response in a way that had not been encountered previously. People who were not vaccinated were most at risk.

Delta posed very different challenges to earlier strains of COVID-19, with its rapid transmission, infectiousness and higher risk of needing hospital care. In August 2021, the Delta variant arrived in New Zealand. As it was more transmissible than previous variants, Delta spread rapidly worldwide and became the main variant in most countries. The Delta variant was first detected in late 2020 and was named a Variant of Concern by the WHO on. Read about COVID-19 testing and waste water testing. Ongoing wastewater surveillance is also used to monitor the variants circulating in the community. This helps identify which new variants are arriving in the country. In New Zealand individuals arriving from overseas who have a positive RAT test are asked to have a follow-up PCR test so that WGS can be performed.

This is possible through PCR testing but not through rapid antigen testing (RAT). Whole-genome sequencing (WGS) is required to identify which variant a person is infected with. Regular updates on COVID-19 variants are published on the Science News page. The Ministry of Health regularly reviews recent international developments with respect to the identification of new COVID-19 variants or further details about the properties of already identified variants, and monitors characteristics of current circulating variants. Read more: Tracking SARS-CoV-2 variants вЂ“ World Health Organization Variant updates The World Health Organization (WHO) and its international networks of experts monitor changes to the virus so that if significant changes to the virus structure are identified that would necessitate an updated public health response, countries and the public can respond to theВ variant andВ try to prevent itsВ spread. VOIs that change the way the virus behaves are called вЂњVariants of ConcernвЂќ (VOCs).Дuring late 2020, the emergence of variants that posed an increased risk to global public health prompted the characterisation of specific VOIs and VOCs, in order to prioritise global monitoring and research, and ultimately to inform the ongoing response to the COVID-19 pandemic. There are many different variants and those that have had changes to the virusвЂ™s properties are called вЂњVariants of InterestвЂќ (VOI) and are monitored more closely. However, some changes may affect how easily the virus spreads, the disease severity, the ability of vaccines to prevent disease or the effectiveness of treatments, diagnostic tools, or other public health and social measures. Most changes have little to no impact on the virusвЂ™ properties. All viruses, including SARS-CoV-2, the virus that causes COVID-19, change over time.

Delta variant origin