The highly contagious Delta variant of Covid-19 was found to be circulating in areas with low vaccine coverage and driving transmission of coronavirus disease around the world, the World Health Organisation (WHO) said on Wednesday. It cautioned that the Delta variant was spreading even in countries with high vaccination rates at the national level.

“Many of the places around the world where Delta is surging — even in countries that at a national level have high levels of vaccination coverage — the virus, the Delta variant itself, is really circulating in areas of low level of vaccine coverage and in the context of very limited and inconsistent use of public health and social measures,” WHO epidemiologist Maria Van Kerkhove told an online news briefing, reported Reuters.

WHO chief scientist Soumya Swaminathan told Reuters on Wednesday that Covid-19 vaccines offer protection against death and severe illness but cautioned that there’s no need for administering booster shots at the moment. “We believe clearly that the data today does not indicate that boosters are needed,” Swaminathan said.

A recent study conducted at the Washington University School of Medicine showed that the Delta variant of the SARS-CoV-2 virus was unable to evade all but one of the antibodies generated post-vaccination.

The researchers analysed a panel of antibodies generated by people who had been inoculated with the Pfizer-BioNTech vaccine. The research was carried out on four variants of concern: Alpha, Beta, Gamma and Delta on 13 antibodies grown in the lab from antibody growing cells in three vaccinated individuals. 12 of the 13 antibodies recognised Alpha and Delta, eight recognised all four variants, and one failed to recognise any of the four variants.