The vaccine is made by the National Institutes of Health and Moderna Inc.
Public Health England (PHE), in a pre-print, said that the Pfizer/BioNTech COVID-19 vaccine was 96% effective against hospitalization from the Delta variant after two doses, while Oxford/AstraZeneca's offered 92% protection against hospitalization by that variant.
While the data provides additional evidence that two doses of those COVID-19 vaccines still protect against severe disease, it suggested that vaccine effectiveness against milder symptomatic disease, although significant, was lower.
However, the secretary maintained that people who have received both jabs should be protected by the new variant.
When the Alpha, or United Kingdom variant, was dominant in the United Kingdom, the symptoms most strongly linked to infection were chills, muscle aches, loss of appetite and headaches.
Biden leaves Washington to meet allies -- then Putin
Biden, 78, heads from the White House first to Britain ahead of a G7 summit in a Cornish seaside resort from Friday to Sunday. Trump argued that the United States can't afford to be the world's policeman, an isolationist stance popular with his voters.
Dr. Ben Weston, with the Medical College of Wisconsin and Milwaukee County Office of Emergency Management, said the good news is the vaccines appear to be effective against the Delta variant.
According to Health Canada, it accounted for a majority of COVID-19 cases identified in March and April.
Researchers found that two doses of both the AstraZeneca and Pfizer vaccines were effective in reducing hospitalizations among people who had contracted the Delta strain, but the effectiveness of the shots was "diminished" when to compared to those with the Alpha variant. The findings also concluded that the Delta variant affected the younger more affluent group.
Dr. Gerald Evans, chair of infectious diseases at Queen's University, said there could be a variety of reasons for this.
Although being infected with this variant of coronavirus may feel more like "a bad cold" for younger people, Professor Tim Spector, who runs the Zoe Covid Symptom study, has warned it is more transmissible and could seriously affect others if safety measures aren't adhered to. Experts say it could potentially be evolution of the virus, but it may also have something to do with the age of those infected. "One dose isn't enough".