The vaccine developed by the University of Oxford and AstraZeneca not only protects people from serious illness and death, but also substantially slows the transmission of the virus, according to a new study – a finding that underscores the importance of mass vaccination as a pathway to out of the pandemic.
Researchers at the University of Oxford measured the impact on transmission by collecting samples from participants every week, looking for signs of the virus. If there is no virus present, even if someone is infected, it cannot be transmitted. And they found a 67 percent reduction in positive swabs among those vaccinated.
The results, detailed by researchers at Oxford and AstraZeneca in a manuscript that was not peer-reviewed, found that the vaccine can reduce transmission by almost two-thirds.
Matt Hancock, the British health secretary, welcomed the results on Wednesday as “absolutely excellent”.
“Now we know that the Oxford vaccine also reduces transmission and that will help us to get out of this pandemic,” said Hancock in an interview on Wednesday morning for the BBC.
The results, he said, “should give everyone confidence that this jab works not only to keep you safe, but also to prevent you from passing the virus on to others.”
Some scientists, examining the limited information released, warned that further analysis of the data was needed before such broad conclusions could be firmly established.
“While this is extremely welcome news, we need more data before it can be confirmed and that is why it is important that we all continue to follow the social detachment guidelines after we have been vaccinated,” said Dr. Doug Brown, executive chairman of the British Immunology Society.
The Oxford and AstraZeneca researchers also found that a single dose of the vaccine was 76 percent effective in preventing Covid-19. The data measured three months after the first injection was given, not including an initial three-week period needed for the protection to take effect.
The encouraging results support the strategy implemented by Britain and other countries to prioritize the provision of as many first doses of vaccines as possible, leaving aside concerns that people will receive their second doses later than originally planned.
The most recent data does not influence the debate over the larger dose spacing of the two vaccines authorized in the United States, those of Pfizer-BioNTech and Moderna, as the data from the AstraZeneca candidate cannot be generalized to other vaccines.
Some scientists have asked the United States to follow the example of Britain and other countries that have chosen to postpone second doses of vaccines for up to 12 weeks. But US federal officials resisted, saying that such a move would not be supported by clinical trial data for the two vaccines currently available across the country. Tuesday’s results could increase pressure on US health officials to delay second doses of the AstraZeneca vaccine, although it has not yet been authorized by the country.
The vaccine seemed more effective when the interval between the two injections was longer than the originally intended four-week interval, the Oxford and AstraZeneca researchers found. Among clinical trial participants who received two doses of standard strength at least three months apart, the vaccine was 82 percent effective, compared to 55 percent effective when doses were administered less than six weeks apart.
Vaccines for covid19>
Answers to your vaccine questions
Currently, more than 150 million people – almost half the population – can be vaccinated. But each state makes the final decision about who goes first. The country’s 21 million health workers and three million residents in long-term care facilities were the first to qualify. In mid-January, federal authorities urged all states to open eligibility for all people aged 65 and over and adults of any age with medical conditions that put them at high risk of becoming seriously ill or dying from Covid-19. . Adults in the general population are at the rear of the line. If federal and state health officials can resolve bottlenecks in vaccine delivery, all 16 years and older will be eligible as early as this spring or early summer. The vaccine has not been approved in children, although studies are ongoing. It may take months before a vaccine is available to anyone under the age of 16. Go to your state’s health website for up-to-date information on vaccination policies in your area
You should not have to pay anything out of your pocket to get the vaccine, although insurance information is requested. Even if you are not insured, you should receive the vaccine free of charge. Congress passed legislation this spring that prohibits insurers from applying any cost sharing, such as copayment or deductibles. He imposed additional protections, preventing pharmacies, doctors and hospitals from charging patients, including those without insurance. Even so, health experts fear that patients may run into gaps that leave them vulnerable to unexpected bills. This can happen for those who pay a medical consultation fee with their vaccine, or Americans who have certain types of health coverage that do not fall under the new rules. If you get the vaccine at a doctor’s office or urgent care clinic, talk to them about possible hidden costs. To make sure you don’t get a surprise bill, the best bet is to get your vaccine at a vaccination post in the health department or at a local pharmacy as soon as the vaccines are more widely available.
This must be determined. It is possible that Covid-19 vaccines will become an annual event, as well as the flu vaccine. Or it may be that the benefits of the vaccine last for more than a year. We have to wait to see how durable vaccine protection is. To determine this, the researchers will screen vaccinated people for “innovative cases” – those who fall ill with Covid-19 despite the vaccination. This is a sign of weakened protection and will give researchers clues as to how long the vaccine lasts. They will also monitor the levels of antibodies and T cells in the blood of vaccinated people to determine if and when a booster injection may be needed. It is conceivable that people need reinforcements every few months, once a year or just every few years. It is just a matter of waiting for the data.
A vaccination strategy that spans doses by three months “may be ideal for launching a pandemic vaccine when supplies are limited in the short term,” the researchers wrote.
The newly released study is based on data published last year, which found that the vaccine was 62 percent effective when given in two standard doses. In these initial findings, the vaccine’s effectiveness was much higher, 90 percent, when the first dose of the vaccine was given at half strength.
The Oxford and AstraZeneca researchers initially attributed the different levels of effectiveness to the lower strength of the initial dose. But little by little they came to a different conclusion: the amount of time between doses was the most likely explanation.
In the United States, the Food and Drug Administration is awaiting data from a clinical trial involving nearly 30,000 participants, most of whom are Americans. The results of that study are expected later this month.
The study is expected to provide AstraZeneca with sufficient safety data to allow, around the beginning of March, to obtain authorization to supply the vaccine for emergency use.
The United States has agreed to buy 300 million doses of AstraZeneca vaccine, but neither the company nor the federal government has said when and in what quantities these doses will be available after the vaccine is approved.