The highly contagious Delta variant of the coronavirus is gaining ground in Italy, the National Health Institute (ISS) said on Friday, releasing data showing it accounted for some 22.7% of cases as of June 22, Reuters reported. 

In the previous such survey based on data from May 18, the Delta variant represented just 1% of cases. By contrast, the Alpha variant accounted for 57.8% of cases as of June 22 against a previous 88.1%.

"In Italy, where the vaccination campaign has not yet achieved sufficient coverage, the spread of more transmissible variants may have a significant impact", the institute said.

According to the Reuters report, the Delta variant, first detected in India in December 2020 year, has spread to about 100 countries and the World Health Organization warned recently that it could soon become the dominant form of the virus.

The ISS said its survey did not include all variant cases but only those detected on the day it was carried out. It added that the Kappa variant had not been found on that day despite several cases being signaled at other times.

The data also showed a rise in the Gamma variant, first identified in Brazil, to 11.8% of cases from 7.3% in the past survey.

Italy has registered 127,587 deaths linked to COVID-19 since its outbreak emerged in February last year, the second-highest toll in Europe after Britain and the eighth-highest in the world. The country has reported 4.26 million cases to date.

Studies released in Britain last month showed the Delta variant doubled the risk of hospitalization, but that two doses of vaccine provided strong protection. Some 32.2% of Italians are fully vaccinated, while 25.6% are awaiting a second dose.

(With input from agencies)