Omicron has been the latest variant to test the effectiveness of COVID-19 vaccines.

COVID-19 vaccines appear to have become less effective in preventing severe COVID-19 disease and death, but they still provide ‘significant protection’, says the World Health Organisation (WHO), according to Reuters.

The Omicron variant, first detected in South Africa and Hong Kong, S.A.R., China last month, has now been reported by 77 countries. WHO director general Tedros Adhanom Ghebreyesus emphasised that it should not be dismissed as “mild”.

“Omicron is spreading at a rate we have not seen with any previous variant,” Tedros told an online briefing. “Even if Omicron does cause less severe disease, the sheer number of cases could once again overwhelm unprepared health systems. Evolving evidence suggests a small decline in the effectiveness of vaccines against severe disease and death, and a decline in preventing mild disease or infection.”

Tedros added that vaccine booster shots can play an important role in curbing the spread of Omicron, as long as people most in need of protection receive access to jabs.

Mike Ryan, WHO’s emergencies director, expressed that the vaccines are not failing and provide significant protection against severe disease and death. “The question is how much protection are the current vaccines that we are using, which are currently life-saving against all the variants, and to what extent do we lose any protection against severe illness and death against Omicron. The data is pointing towards there being significant protection.”

While there is still further evidence needed to evaluate whether Omicron is less harmful than Delta, current hospitalisation rates indicate that the new variant is causing fewer infections. The NHS is still facing the threat of becoming overwhelmed in the coming months due to the alarming rate at which Omicron is rising.