A new wave of coronavirus infections is "definitely under way" in England due to the Delta variant first identified in India, a British government advisory scientist said on Saturday.
"The race is firmly on between the vaccine program... and the Delta variant third wave," said professor Adam Finn, a member of the Joint Committee on Vaccination and Immunisation (JCVI), Xinhua news agency reported.
Acknowledging the recent surge in infections, Finn told the BBC: "Perhaps we can be a little bit optimistic it's not going up any faster, but nevertheless it's going up -- so this third wave is definitely under way."
Noting that the highest number of cases of the Delta variant is among 16-25 year-olds, Finn said that older people are still "much more likely to end up in hospital."
"As far as vaccines are concerned, the main emphasis everywhere at the moment is immunising adults because it's adults that suffer predominantly from this infection," he said.
Meanwhile, epidemiologist Mike Tildesley said he is "cautiously hopeful" that hospital admissions in Britain will not be on the same scale as in January.
Tildesley, a member of the Scientific Pandemic Influenza Group on Modelling (SPI-M), another government advisory body, said cases have been "creeping steadily" over the past month "but we haven't yet seen that reflected in hospital admissions and deaths".
"I'm cautiously hopeful that whilst we probably will expect some sort of wave of hospital admissions over the next few weeks, it won't be the same scale that we saw back in January."
The recent data published by Public Health England showed the AstraZeneca vaccine is 92 percent effective against hospitalisation from the Delta variant after two doses, and the Pfizer vaccine is 96 percent effective against hospitalization after two doses.
More than 42.4 million people have been given the first jab of a coronavirus vaccine while more than 30.8 million people have been fully vaccinated with a second dose, according to the latest official figures.
Experts have warned that coronavirus may continue to evolve for years to come, and eventually it is likely current vaccines will fail to protect against transmission, infection, or even against disease caused by newer variants.