An assessment of the potential impact of the Omicron variant of SARS-CoV-2 in Aotearoa New Zealand

Vattiato, Giorgia; Maclaren, Oliver J.; Lustig, Audrey; Binny, Rachelle N.; Hendy, Shaun C.; Plank, Michael J.

doi:10.1016/j.idm.2022.04.002

Cited by 14 publications

(20 citation statements)

References 27 publications

(33 reference statements)

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“…This model included the effects of age-specific vaccination rates, different vaccine effectiveness against different clinical endpoints, and waning of vaccine-derived immunity. The model results were reasonably consistent with the observed numbers of cases, hospitalisations and deaths during the first Omicron wave up to early April 2022 ( Vattiato et al, 2022 ). However, the model did not include the effects of waning of infection-derived immunity, meaning that people could not be infected with the virus for a second time.…”

Section: Introductionsupporting

confidence: 81%

See 1 more Smart Citation

Modelling the dynamics of infection, waning of immunity and re-infection with the Omicron variant of SARS-CoV-2 in Aotearoa New Zealand

Vattiatio

Lustig²,

Maclaren

et al. 2022

Epidemics

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Section: Introductionsupporting

confidence: 81%

“…We have previously modelled the spread and impact of the Omicron variant of SARS-CoV-2 in New Zealand using an age-structured model ( Vattiato et al, 2022 ). This model included the effects of age-specific vaccination rates, different vaccine effectiveness against different clinical endpoints, and waning of vaccine-derived immunity.…”

Section: Introductionmentioning

confidence: 99%

Modelling the dynamics of infection, waning of immunity and re-infection with the Omicron variant of SARS-CoV-2 in Aotearoa New Zealand

Vattiatio

Lustig²,

Maclaren

et al. 2022

Epidemics

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“…6 ). Epidemiological models from earlier in the year predicted that a second wave was likely to arise in August or September 2022 due to the nation’s waning population immunity, but they noted that a variant with a growth advantage could bring that wave forward 29 , 30 . It turned out that BA.4 and BA.5 were the new variants that caused the wave, with case data showing a peak of the second wave, dominated by BA.5, occured in mid-July with cases now declining.…”

Section: Discussionmentioning

confidence: 99%

Tracing the international arrivals of SARS-CoV-2 Omicron variants after Aotearoa New Zealand reopened its border

et al. 2022

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In the second quarter of 2022, there was a global surge of emergent SARS-CoV-2 lineages that had a distinct growth advantage over then-dominant Omicron BA.1 and BA.2 lineages. By generating 10,403 Omicron genomes, we show that Aotearoa New Zealand observed an influx of these immune-evasive variants (BA.2.12.1, BA.4, and BA.5) through the border. This is explained by the return to significant levels of international travel following the border’s reopening in March 2022. We estimate one Omicron transmission event from the border to the community for every ~5,000 passenger arrivals at the current levels of travel and restriction. Although most of these introductions did not instigate any detected onward transmission, a small minority triggered large outbreaks. Genomic surveillance at the border provides a lens on the rate at which new variants might gain a foothold and trigger new waves of infection.

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“…Under the current border settings we estimated there is approximately one transmission event into the community for every 5,000 passenger arrivals into the country (Figure 6). Epidemiological models from earlier in the year predicted that a second wave was likely to arise in August or September 2022 due to waning population immunity, but they noted that a variant with a growth advantage could bring that wave forward [25,26]. This could occur imminently after BA.5 gains a foothold in the community, and this is likely to happen sooner with increased international travel.…”

Section: Discussionmentioning

confidence: 99%

Tracing the international arrivals of SARS-CoV-2 Omicron variants after Aotearoa New Zealand reopened its border

Douglas

Winter

Ren

et al. 2022

Preprint

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Recently there has been a surge in emergent SARS-CoV-2 lineages that are able to evade both vaccine induced immunity as well as prior infection from the founding Omicron BA.1 and BA.2 lineages. These highly transmissible and evasive lineages are on the rise and include Omicron variants BA.2.12.1, BA.4, and BA.5. Aotearoa New Zealand recently reopened its borders to many travellers, without their need to enter quarantine. By generating 10,403 complete SARS-CoV-2 genomes classified as Omicron, we show that New Zealand is observing an influx of these immune-evasive variants through the border. Specifically, there has been a recent surge of BA.5 and BA.2.12.1 introductions into the community and these can be explained by the gradual return to pre-pandemic levels of international traveller arrival rates. We estimate there is one Omicron transmission event from the border to the community for every ~5,000 passenger arrivals into the country, or around one introduction event per day at the current levels of travel. Given the waning levels of population immunity, this rate of importation presents the risk of a large wave in New Zealand during the second half of 2022. Genomic surveillance, coupled with modelling the rate at which new variants cross the border into the community, provides a lens on the rate at which new variants might gain a foothold and trigger new waves of infection.

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An assessment of the potential impact of the Omicron variant of SARS-CoV-2 in Aotearoa New Zealand

Cited by 14 publications

References 27 publications

Modelling the dynamics of infection, waning of immunity and re-infection with the Omicron variant of SARS-CoV-2 in Aotearoa New Zealand

Modelling the dynamics of infection, waning of immunity and re-infection with the Omicron variant of SARS-CoV-2 in Aotearoa New Zealand

Tracing the international arrivals of SARS-CoV-2 Omicron variants after Aotearoa New Zealand reopened its border

Tracing the international arrivals of SARS-CoV-2 Omicron variants after Aotearoa New Zealand reopened its border

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