Omicron raises reinfection fears as more cases emerge

The Omicron variant of the coronavirus appears to be at least 2.4 times more likely to reinfect people than the original strain, according to early data from South Africa, where the variant is surging.

Scientists at South Africa’s National Institute for Communicable Diseases (NICD) say the latest epidemiological evidence suggests Omicron is causing reinfections at an increased rate.

Anne von Gottberg, a microbiologist at the NICD, said there seemed to be early signs that previous infection did not provide the same levels of immunity against Omicron as it had against the Delta strain.

Von Gottberg said doctors were seeing ‘‘an increase for Omicron reinfections’’.

‘‘We believe the number of cases will increase exponentially in all provinces of the country, she said. ‘‘We believe that vaccines will still, however, protect against severe disease.’’

The Omicron variant has now become the dominant mode of infection in South Africa. About 11,535 new infections were registered yesterday, up from 8561 the day before – an increase of 368 per cent. In mid-November, South Africa had been reporting about 300 cases a day.

The scientists at the NICD looked at almost 2.8 million confirmed cases in South Africa since March 2020, and found that 35,670 were reinfections. They found that the risk of reinfection due to Omicron is 2.4 times higher than in the first wave.

Scientists have cautioned that early reports suggesting that the Omicron variant may cause less severe illness than previous strains were because the first cases were identified in younger people, who would be expected to have fairly mild symptoms.

Omicron has raised concerns because it carries an unprecedented number of mutations, including about 30 on its important spike protein, which may lower immunity from vaccines and previous infections. Other mutations have been linked to greater transmissibility in previous variants. It has been detected in at least 24 countries, according to the World Health Organisation.

■ With the Delta variant of Covid19 pushing up case numbers in Europe, and growing fears over the Omicron variant, governments are considering new measures for populations tired of restrictions and vaccines.

In Greece, residents over 60 face fines of €100 (NZ$166) a month if they fail to get vaccinated. About 17 per cent of Greeks over 60 are unvaccinated, and nine in 10 Greeks now dying of Covid-19 are over 60.

Employing a carrot instead of a stick, Slovakia’s government is proposing to give people 60 and older a €500 (NZ$832) bonus if they get vaccinated.

Germany yesterday imposed strict new limitations on the unvaccinated, excluding them from non-essential stores, restaurants and other major public venues. They can go to work only with a negative test.

Chancellor Angela Merkel said the measures were necessary because hospitals risked becoming overloaded.

At least 50 people in and around Norway’s capital have been infected with the Omicron variant, and the cases are connected to a Norwegian company’s Christmas party at an Oslo restaurant, officials say.

The Norwegian government said new national and regional restrictions would take effect. Anyone entering Norway must take a Covid-19 test within 24 hours.

Just a day after the first known United States case was found, in California, tests yesterday showed that the Omicron variant had infected at least five people in the New York City metropolitan area, plus a man from Minnesota who had attended an anime convention in Manhattan in late November.

US President Joe Biden announced an array of measures to protect Americans from the virus, including campaigns to increase vaccinations and booster shots, more stringent testing requirements for international travellers, and plans to make rapid at-home coronavirus testing free for more people.

Public health experts said new measures to ward off the virus were overdue, lamenting the slow pace of vaccinations, the rise of misinformation that has fuelled vaccine hesitancy, and other factors they said had left the nation vulnerable to a potential winter surge of infections.

■ A school student with no link to overseas travellers is the latest confirmed case of the Omicron variant in New South Wales, stoking fears that the new strain is circulating in the community.

The student’s case takes the number of confirmed Omicron cases in NSW to nine. The state’s vaccination rates are 94.6 per cent first-dose coverage and 92.6 per cent double-dosed.

– The Times, AP, Washington Post, AAP