Omicron risk remains very high: WHO; Covid-hit Australian warship delivers disaster aid to Tonga

London: Nearly two-thirds of people in England who tested positive for Covid-19 in January previously had the virus or suspected they had it, a large long-running infection survey revealed on Wednesday.

The finding, in the latest report on coronavirus transmission by Imperial College London, is seen as further evidence of the Omicron variant’s ability to dodge the immune systems of those previously infected with the virus.

As part of its regular assessment, Imperial received around 100,000 valid swap tests self-administered by a random sample of people across England between January 5 and 20. Approximately 4,000 showed a positive result, and nearly 3,600 of those individuals specified whether or not they had had Covid before.

Around 65 percent of those respondents had previously tested positive, while a further 7.5 percent said they suspected they had caught the virus previously but had not received a confirmatory test.

"Past infection was associated with high risk of reinfection with Omicron," the study’s authors noted in its abstract. However Paul Elliott, who directs the Imperial study, noted not all these cases could be confirmed as reinfections because some could be residual illness, meaning a person had tested positive twice for the same infection.

But the numbers reporting reinfections in the study are markedly higher than those published by the UK Health Security Agency, a public health protection body. Its latest figures show 11 percent of all English cases were reinfections.

The UKHSA said on Wednesday it would begin including reinfections data on the government’s rolling coronavirus data dashboard from the end of the month. A reinfection is defined as a person testing positive twice at least 90 days apart.

The Imperial survey also confirmed Omicron, which has swept the UK since late November, is now responsible for nearly all new infections in England. Positive cases among its randomly selected sample were three times higher in the January sampling period than the previous month, it found.

"We observed unprecedented levels of infection with SARS-CoV-2 in England in January 2022 and almost complete replacement of Delta by Omicron," the report said. However, the study detected that the prevalence of the virus among adults was starting to decline.

England on Thursday will lift the last of various virus curbs reimposed last month as Omicron surged nationwide, including the requirement to wear masks in most settings. A so-called Covid pass system for nightclubs will also be scrapped, as the country returns to its lowest level of restrictions of any stage of the pandemic.

Meanwhile, the risk level related to the Omicron variant remains very high, the WHO said on Wednesday, with the numbers of new Covid-19 cases hitting another record high last week. "Over 21 million new cases were reported, representing the highest number of weekly cases recorded since the beginning of the pandemic," the World Health Organisation said in its weekly epidemiological coronavirus update.

The UN health agency said the number of new infections increased by five percent in the week to Sunday -- compared to the 20 percent rise registered the week before. "A slower increase in case incidence was observed at the global level," the WHO said.

Nearly 50,000 new deaths were also reported, it added -- a similar figure to the week before. The report said Omicron continued to increase its dominance globally over the other variants of concern.

"The current global epidemiology of SARS-CoV-2 is characterised by the dominance of the Omicron variant on a global scale, continued decline in the prevalence of the Delta variant, and very low-level circulation of Alpha, Beta and Gamma variants," the WHO said.

"Countries that experienced a rapid rise in Omicron cases in November and December 2021 have been or are beginning to see declines in cases. However, "based on the currently available evidence, the overall risk related to the Omicron variant remains very high".

The WHO said that of samples collected in the last 30 days that have been sequenced and uploaded to the GISAID global science initiative, Omicron accounted for 89.1 percent. Delta -- previously the world’s dominant variant -- now makes up 10.7 percent.

Meantime, a coronavirus-hit Australian warship docked in Tonga on Wednesday, delivering desperately needed aid to the volcano-and-tsunami-struck nation under strict "no-contact" protocols.

Tongan Health Minister Saia Piukala said the crew of the HMAS Adelaide would follow drastic health protocols to ensure the remote Pacific kingdom remains one of the few places in the world still free of Covid-19.

"The ship will berth and no contacts will be made. Australians from the ship will unload their cargoes and sail from port," he told reporters. The Adelaide was deployed as part of an international aid effort after the January 15 eruption that generated massive tsunami waves and blanketed the island nation in toxic ash.

The warship is carrying about 80 tonnes of relief supplies, including water, medical kits and engineering equipment. Despite all crew members testing negative before departing Brisbane, officials in Canberra on Tuesday said 23 coronavirus cases had been detected on the vessel.

Piukala said that number had increased to 29 by Wednesday. The ship’s 600-plus crew are fully vaccinated, and the Australian Defence Force said on Wednesday that the initial 23 patients were asymptomatic or only mildly affected.

It said the ship has a 40-bed hospital, including operating theatres and a critical care ward. Piukala said contactless protocols were being applied to all relief supplies, including those aboard the HMAS Adelaide, meaning all goods offloaded from foreign planes or ships would be left in isolation for three days before being handled by Tongans.

The ship is said to be loaded with about 250,000 litres (66,000 US gallons) of water, buckets, jerry cans and portable field-testing kits that can now be offloaded. "We can do that in a contactless way, spray the equipment so that the chance of passing on the virus is obviously negligible," Australian Defence Minister Peter Dutton said on Wednesday.

"Under no circumstance will we compromise the health and well-being of those Tongans who have already had a concerted effort against the virus by protecting themselves, and the virus is not present on the island."

But coronavirus restrictions are already hampering the aid effort in other ways. Japan has announced its aid aircraft will pause trips between Australia and Tonga due to four Covid-19 cases among the mission’s staff.

"We are making sure that the impact on the mission is minimal, and once our review of anti-infection measures is completed, we’ll continue the mission," a defence ministry official told AFP.

Tonga closed its borders in early 2020 as the coronavirus pandemic swept the globe. Since then, the nation of 100,000 has recorded just one Covid-19 case, a man who returned from New Zealand in October last year and has since fully recovered.

However, the devastating blast from the Hunga Tonga-Hunga Ha’apai volcano, which lies about 65 kilometres (40 miles) north of the capital Nuku’alofa, has created what the Tongan government describes as an "unprecedented disaster".

Entire villages were washed away by tsunamis, while ash has poisoned water supplies and destroyed crops. Remarkably, there have been only three reported fatalities, which the UN humanitarian agency OCHA said was thanks to effective early warnings issued by the Tongan government.

OCHA said communications severed by the eruption were slowly being restored and assessment teams were visiting hard-to-reach areas to gauge the full scale of the disaster. It said 85 percent of Tonga’s population had been affected, with access to safe water, ash clearance and food supplies the main priorities.