LONDON: A third shot of the Oxford-AstraZeneca COVID-19 vaccine produces a strong immune response, researchers said on Monday, adding there was not yet evidence that such shots were needed, especially given shortages in some countries.
The Oxford University study found that a third dose of the vaccine increases antibody and T-cell immune responses, while the second dose can be delayed up to 45 weeks and also lead to an enhanced immune response.
The British government has said it is looking at plans for an autumn vaccine booster campaign, with three-fifths of adults already having received both doses of a COVID vaccine.
Andrew Pollard, director of the Oxford Vaccine Group, said that evidence that the vaccine protects against current variants for a sustained period of time meant that such a booster may not be needed.
"We do have to be in a position where we could boost if it turned out that was necessary ... (but) we don't have any evidence that that is required," he told reporters.
"At this point with a high level of protection in the UK population and no evidence of that being lost, to give third doses now in the UK whilst other countries have zero doses is not acceptable."
Studies had previously shown that the shot, invented at Oxford University and licensed to AstraZeneca has higher efficacy when the second dose is delayed to 12 weeks instead of four weeks.
Monday's research was released in a preprint, and looked at 30 participants who received a late second dose and 90 who received a third dose, all of whom were under 55.
It helps assuage concerns that viral vector COVID vaccines, such as those made by AstraZeneca and Johnson & Johnson, may lose their potency if annual inoculations are needed due to the risk that the body produces an immune response against the vectors that deliver the vaccine's genetic information.
"There had been some concerns that we would not be able to use this vaccine in a booster vaccination regime, and that's certainly not what the data is suggesting," study author Teresa Lambe of Oxford's Jenner Institute told Reuters.
Meanwhile, another Oxford study said on Monday that amixed schedule of vaccines where a shot of Pfizer’s COVID-19 vaccine is given four weeks after a AstraZeneca shot will produce better immune responses than giving another dose of the AstraZeneca shot.
The study, called Com-COV, compared mixed two-dose schedules of Pfizer and AstraZeneca vaccines, and found that in any combination, they produced high concentrations of antibodies against the coronavirus spike protein.
The data provides support for the decision of some European countries that have started offering alternatives to AstraZeneca as a second shot after the vaccine was linked to rare blood clots.
Matthew Snape, the Oxford professor behind the trial, said that the findings could be used to give flexibility to vaccine rollouts, but was not large enough to recommend a broader shift away from clinically approved schedules on its own.
“It’s certainly encouraging that these antibody and T-cell responses look good with the mixed schedules, but I think your default has to stay, unless there’s a very good reason otherwise, to what is proven to work,” he told reporters.
The highest antibody response was seen in people receiving two doses of Pfizer vaccine, with both mixed schedules producing better responses than two doses of AstraZeneca vaccine.
An AstraZeneca shot followed by Pfizer produced the best T-cell responses, and also a higher antibody response than Pfizer followed by AstraZeneca.
The results were for combinations of vaccines given at four week intervals to 830 participants.
Oxford COVID vaccine produces strong immune response from booster shot - study
https://arab.news/8pe6g
Oxford COVID vaccine produces strong immune response from booster shot - study
- Oxford University study found a third dose of the vaccine increases antibody and T-cell immune responses
- Immune response of AstraZeneca shot boosted by mixing dose schedule with Pfizer, Oxford study reveals
Uganda’s presidential election experiences hours of delays at some polling stations
- Some polling stations remained closed for up to four hours after the scheduled 7 a.m. start time due to “technical challenges“
- The East African country of roughly 45 million people has 21.6 million registered voters
KAMPALA, Uganda: Uganda’s presidential election was plagued by widespread delays Thursday in addition to a days-long Internet shutdown that has been criticized as an anti-democratic tactic in a country where the president has held office since 1986.
Some polling stations remained closed for up to four hours after the scheduled 7 a.m. start time due to “technical challenges,” according to the nation’s electoral commission, which asked polling officers to use paper registration records to ensure the difficulties did not “disenfranchise any voter.”
President Yoweri Museveni, 81, faces seven other candidates, including Robert Kyagulanyi, a musician-turned-politician best known as Bobi Wine, who is calling for political change.
The East African country of roughly 45 million people has 21.6 million registered voters. Polls are expected to close at 4 p.m. Thursday, according to the electoral commission. Results are constitutionally required to be announced in 48 hours.
Impatient crowds gathered outside polling stations expressing concerns over the delays Thursday morning. Umaru Mutyaba, a polling agent for a parliamentary candidate, said it was “frustrating” to be waiting outside a station in the capital Kampala.
“We can’t be standing here waiting to vote as if we have nothing else to do,” he said.
Wine alleged there was electoral fraud occurring, noting that biometric voter identification machines were not working at polling places and claiming there was “ballot stuffing.”
“Our leaders, including Deputy President for Western Region, arrested. Many of our polling agents and supervisors abducted, and others chased off polling stations,” Wine wrote in a post on social media platform X.
Museveni told journalists he was notfied biometric machines were inoperable at some stations and he supported the electoral body’s decision to revert to paper registration records. He did not comment on the allegation of fraud.
Ssemujju Nganda, a prominent opposition figure and lawmaker seeking reelection in Kira municipality, told The Associated Press he had been waiting in line to vote for three hours.
Nganda also noted biometric machines were malfunctioning, in addition to the late arrival of balloting materials, and predicted the delays likely would lead to apathy and low turnout in urban areas where the opposition has substantial support.
“It’s going to be chaos,” he said Thursday morning.
Nicholas Sengoba, an independent analyst and newspaper columnist, said delays to the start of voting in urban, opposition areas favored the ruling party.
Museveni serving Africa’s third-longest presidential term
Uganda has not witnessed a peaceful transfer of presidential power since independence from British colonial rule six decades ago.
Museveni has served the third-longest term of any African leader and is seeking to extend his rule into a fifth decade. Some critics say removing him through elections remains difficult, but the aging president’s authority has become increasingly dependent on the military led by his son, Muhoozi Kainerugaba.
Museveni and Wine are reprising their rivalry from the previous election in 2021, when Wine appealed to mostly young people in urban areas. With voter turnout of 59 percent, Wine secured 35 percent of the ballots against Museveni’s 58 percent, the president’s smallest vote share since his first electoral campaign three decades ago.
The lead-up to Thursday’s election produced concerns about transparency, the possibility of hereditary rule, military interference and opposition strategies to prevent vote tampering at polling stations.
Uganda’s Internet was shut down Tuesday by the government communications agency, which cited misinformation, electoral fraud and incitement of violence. The shutdown has affected the public and disrupted critical sectors such as banking.
Heavy security deployed
There has been heavy security leading up to voting, including military units deployed on the streets this week.
Amnesty International said security forces are engaging in a “brutal campaign of repression,” citing a Nov. 28 opposition rally in eastern Uganda where the military blocked exits and opened fire on supporters, killing one person.
Museveni urged voters to come out in large numbers during his final rally Tuesday.
“You go and vote, anybody who tries to interfere with your freedom will be crushed. I am telling you this. We are ready to put an end to this indiscipline,” he said.
The national electoral commission chairperson, Simon Byabakama, urged tolerance among Ugandans as they vote.
“Let us keep the peace that we have,” Byabakama said late Wednesday. “Let us be civil. Let us be courteous. Let’s be tolerant. Even if you know that this person does not support (your) candidate, please give him or her room or opportunity to go and exercise his or her constitutional right.”
Authorities also suspended the activities of several civic groups during the campaign season. That Group, a prominent media watchdog, closed its office Wednesday after the interior ministry alleged in a letter that the group was involved in activities “prejudicial to the security and laws of Uganda.”
Veteran opposition figure Kizza Besigye, a four-time presidential candidate, remains in prison after he was charged with treason in February 2025.
