"We are seeing good immune response in nearly everybody", said Dr. Adrian Hill, director of the Jenner Institute at Oxford University.
"We hope this means the immune system will remember the virus, so that our vaccine will protect people for an extended period", study lead author Andrew Pollard of the University of Oxford said.
Still, much remains unknown about COVID-19 vaccines in development, particularly the staying power of any immune responses and effectiveness in older adults or other specific groups, including people with chronic health problems and ethnic or racial groups more severely affected by the disease.
The news has been welcomed by many, including British Health Secretary Matt Hancock, who tweeted that the United Kingdom had "already ordered 100 million doses of this vaccine, should it succeed".
The company has said it will not seek to profit from the vaccine during the pandemic.
Many experts have said that finding a safe and effective vaccine for the coronavirus is essential to ending the pandemic. Once vaccines clear early safety hurdles, they will need to be tested on thousands of subjects to assure they can be safely administered to millions or billions of healthy people.
Russian Covid-19 Vaccine developers ready to share data with foreign colleagues
Britain's National Cyber Security Centre said the group has been using a variety of tools and techniques including spear-phishing and custom malware known as "WellMess" and "WellMail" .
DHS Chief Travels to Portland, Says City is ‘Under Siege’
Marshals Service refused to comment on their use of unmarked vehicles and denied that Pettibone had been arrested by the agency. Seattle's CHOP zone drew the ire of President Donald Trump , who ripped into Seattle city leaders and Gov.
Comet Neowise captured by Okanagan photographers
However, after sunset, the comet will appear higher in the night sky, which will make it easier to see as the week goes on. For instance, Neowise has been confirmed to be brighter than P/2011 (PANSTARRS), but not as bright as Comet Hale-Bopp.
Prof Hill said that while the test does not prove the vaccine will work, "I think we're a bit more confident it should work this week than last week".
In research published Monday in the journal Lancet, scientists said that they found their experimental Covid-19 vaccine produced a dual immune response in people aged 18 to 55. Common AEs included temporary injection site pain and tenderness, mild-to-moderate headache, fatigue, chills, and feverishness.
The UK signed an agreement for 30 million doses from BioNTech/Pfizer, 60 million doses with Valneva (with the potential for 40 million additional doses) and one million doses of a treatment containing COVID-19 antibodies with AstraZeneca.
"The fact remains we may never get a vaccine and if we do get one, we have to be prepared that it may not be a vaccine which prevents getting the virus, but rather one that reduces symptoms", she said.
But some of these could be reduced by taking paracetamol, the researchers said, adding that there were no serious adverse events from the vaccine.
Monday's positive results centred around immune response, but further testing is needed to see if the vaccine can effectively protect against infection.