A health worker demonstrates a vial of the AstraZeneca-Oxford’s Covid-19 coronavirus vaccine, at Patan Hospital near Kathmandu on January 27, 2021.
MATHEMA PRAKASH | AFP | Getty Images
The UK’s decision to delay the second staging of AstraZeneca-Oxford University coronavirus vaccine has been found to be an effective strategy, according to the results of a new study.
Researchers at Oxford University found that the Covid-19 vaccine was 76% effective in preventing symptomatic disease for three months after a single dose, and in fact the level of efficacy increased with a greater interval long before the first and second doses.
“The efficacy of vaccination after a single standard dose of vaccine from day 22 to day 90 after vaccination was 76% … and a modeling analysis showed that protection did not disappear in that initial 3-month period,” said the study, reviewed by the medical journal Lancet and published Tuesday as an introduction, was found.
The efficacy rate rose to 82.4% when at least 12 weeks before the second dose. When the second dose was given less than six weeks after the first, the efficacy rate was 54.9%.
“These analyzes show that higher vaccine efficacy is achieved with a longer interval between the first and second doses, and that a single dose of vaccine is very effective in the first 90 days, further support the current policy, “the report said.
The current UK strategy is to vaccinate as many people with one initial dose and delay the second dose for up to 12 weeks; the idea is that the first dose provides at least some protection and allows more people to access the vaccines while they are not in short supply.
The decision to delay the increase of the second dose has given rise to controversy, with some questioning whether it could reduce the effectiveness of the vaccine at preventing Covid-19 infection.
However, the UK Joint Committee on Vaccination and Immunization supported the approach. The UK is also delaying the second dose of the Pfizer-BioNTech vaccine, a move that vaccine manufacturers have warned, arguing there is no data to support delays.
The study also provided important data on whether the vaccine is reducing the spread of the virus, a previously unknown issue and an important question for policymakers looking to take lock-in measures that have slowed the economy.
Based on weekly swabs from volunteers in the UK study, they found a 67% reduction in transmission after the first dose of the vaccine.
Effective strategy
This latest study supports the UK government’s conclusion, concluding that vaccination programs “aimed at vaccinating a large proportion of the population with a single dose, with a second dose on given after a period of 3 months, is an effective strategy to reduce disease, and this may be the best point for introducing a pandemic vaccine when there are few substances in the short term. “
The study used further data on follow-up clinical trials into the vaccine. A separate message from AstraZeneca on Wednesday showed that the vaccine also prevented serious illness from Covid-19, with no serious cases and no hospitalization longer than 22 days after the first dose.
The vaccine was approved by the UK drug regulator on 30 December and, as a British-made image, makes up most of the country’s vaccination program, which has been successful so far. .
The UK is on track to become its four main priority groups (over 70s, residents and staff in care homes for the elderly, frontline health and social care workers and older people (clinically injured) by about 15 million people by mid-February.
As of Feb.1, more than 9.6 million people had received the first dose of the vaccine, and just under 500,000 had received two doses, according to government data.
Professor Andrew Pollard, principal investigator of the Oxford vaccine trial, and co-author of the study, said, “this new data provides important evidence for the interim data used by more than 25 regulators including MHRA and EMA to implement the vaccine. emergency use permit. “
“It also supports the policy recommendation of the Joint Committee on Vaccination and Vaccination for a 12-week stimulus interval, as they look for the best approach to its roll-out. -out, and reassures us that people are protected from 22 days after one dose of the vaccine. “
The researchers also hope to report data on the new coronavirus mutations in the coming days, and expect the results to be broadly similar to those reported by vaccine adjuvants already: That the conventional vaccines work against virus mutations.
Germany, France and Sweden do not currently recommend the AstraZeneca vaccine for people over 65, saying there are not enough test data about this age group. The vaccine manufacturer and the UK government have defended the injection, however, and say the available data shows it is safe and effective, with more analysis soon to be available. .