Skip to content
Search

Latest Stories

Omicron more likely to reinfect than Delta, says study

Omicron more likely to reinfect than Delta, says study

THE risk of reinfection with the Omicron coronavirus variant is more than five times higher and it has shown no sign of being milder than Delta, a study showed, as cases soar across Europe and threaten year-end festivities.

The results of the study by Imperial College London were based on UK Health Security Agency and National Health Service data on people who tested positive for Covid-19 in a PCR test in England between Nov. 29 and Dec. 11.


"We find no evidence (for both risk of hospitalisation attendance and symptom status) of Omicron having different severity from Delta," the study said, although it added that data on hospitalisations remains very limited.

"Controlling for vaccine status, age, sex, ethnicity, asymptomatic status, region and specimen date, Omicron was associated with a 5.4-fold higher risk of reinfection compared with Delta," the study, which was dated Dec. 16, added.

The protection afforded by past infection against reinfection with Omicron may be as low as 19 per cent, Imperial College (ICL) said in a statement, noting that the study had not yet been peer reviewed.

The researchers found a significantly increased risk of developing a symptomatic Omicron case compared to Delta for those who were two or more weeks past their second vaccine dose, and two or more weeks past their booster dose.

The study involved AstraZeneca and Pfizer vaccines.

Depending on the estimates used for vaccine effectiveness against symptomatic infection from the Delta variant, this translates into vaccine effectiveness of between 0 per cent and 20 per cent after two doses, and between 55 per cent and 80 per cent after a booster dose.

"This study provides further evidence of the very substantial extent to which Omicron can evade prior immunity given by both infection or vaccination," study lead Professor Neil Ferguson said in ICL's statement.

"This level of immune evasion means that Omicron poses a major, imminent threat to public health."

TOO EARLY?

But Dr Clive Dix, former chair of the UK Vaccine Taskforce, said it was important not to overinterpret the data.

"The conclusions made are based on making assumptions about Omicron where we still don't have sufficient data," Dr Dix said. "For example, we have no data on the cellular immune response which is now probably driving effectiveness of vaccines."

"This is a crucial missing assumption in the modelling."

Some of the conclusions are different to the data emerging from South Africa, where vaccines are holding up well against severe disease and death at present, he said.

"There is a huge amount of uncertainty in these modelled estimates and we can only be confident about the impact of boosters against Omicron when we have another month of real-world data on hospitalisation ICU numbers and deaths," he said.

An earlier study by Britain's SIREN looking at reinfection risk in health workers, which was carried out before Omicron emerged, found that a first coronavirus infection offered 85 per cent protection from a second for the following six months.

The data analysed by Imperial College was based on 333,000 cases, including 122,062 of Delta and 1,846 which were confirmed as the Omicron coronavirus variant through genome sequencing.

Imperial College's Professor Azra Ghani, who co-led the study, described it as "essential for modelling the likely future trajectory of the Omicron wave and the potential impact of vaccination and other public health interventions."

The new findings could accelerate the imposition of tighter restrictions across a number of European countries in a bid to stem the new variant's spread.

(Reuters)

More For You

Minouche Shafik

Shafik served as deputy governor for markets and banking at the Bank of England between August 2014 and February 2017.

Reuters

Starmer appoints Minouche Shafik as chief economic adviser in reshuffle

Highlights:

  • Minouche Shafik named chief economic adviser to Keir Starmer.
  • Darren Jones moves into Downing Street role; James Murray replaces him.
  • Wider reshuffle includes changes in Starmer’s private office and communications.
  • Appointment comes ahead of a budget expected to include further tax rises.

Prime minister Keir Starmer has named Minouche Shafik, a former deputy governor of the Bank of England, as his chief economic adviser. The appointment comes as he looks to strengthen his team ahead of what is expected to be a difficult end to the year.

Keep ReadingShow less
modi putin

Before their formal meeting, Putin offered Modi a ride in his Aurus limousine.

X/@narendramodi

Six key takeaways from the SCO summit

INDIAN prime minister Narendra Modi met Russian president Vladimir Putin and Chinese president Xi Jinping on the sidelines of the Shanghai Cooperation Organisation (SCO) summit in Tianjin, China.

Modi pressed for ending the Ukraine conflict at the earliest, reaffirmed India’s long-standing ties with Russia, and discussed trade and border issues with Xi.

Keep ReadingShow less
Afghanistan earthquake

Afghan volunteers and Taliban security personnel carry an earthquake victim evacuated by a military helicopter from the Nurgal district of Kunar province onn September 1, 2025.

Getty Images

Afghanistan earthquake kills more than 800, thousands injured

A MAJOR rescue operation was underway in Afghanistan on Monday after a powerful earthquake and several aftershocks destroyed homes in a remote mountainous region, killing more than 800 people, according to Taliban authorities.

The quake struck just before midnight and was felt as far as Kabul and in Pakistan’s capital, Islamabad.

Keep ReadingShow less
Ganpati festival

The Ganpati festival celebrates Ganesha as the god of new beginnings, and the god of wisdom and intelligence. (Photo: Getty Images)

Getty Images

Hindu community centre in London damaged in fire after Ganapati Visarjan event

A HINDU community centre in east London caught fire on Saturday evening, causing major damage to the building. The London Fire Brigade brought the fire under control and confirmed that no injuries were reported.

The incident took place at the Shree Sorathia Prajapati Community Centre on Cleveland Road in Ilford, which had been decorated for a Ganapati Visarjan event attended by members of the Hindu community.

Keep ReadingShow less
Modi ,Xi & Putin

Narendra Modi talks with Vladimir Putin and Xi jinping ahead of the Shanghai Cooperation Organization (SCO) Summit 2025 at the Meijiang Convention and Exhibition Centre in Tianjin on September 1, 2025.

Getty Images

SCO declaration slams Pahalgam attack, calls for united action on terror

Highlights:

  • SCO condemns terror attack in Pahalgam and echoes India’s stance on “double standards”.
  • Leaders call for justice for perpetrators of attacks in Pahalgam and Balochistan.
  • Declaration criticises Israeli military strikes in Gaza causing civilian casualties.
  • SCO stresses UN’s central role in global counter-terrorism strategy.

THE SHANGHAI Cooperation Organisation (SCO) on Monday condemned the terror attack in Pahalgam and agreed with India’s position that “double standards” in tackling terrorism are not acceptable.

Keep ReadingShow less