According To The Latest Research, Oxford And Astrazeneca Vaccines Can Reduce The Spread Of Coronavirus.
2021-02-03 | by CusiGO
Drug vaccines from AstraZeneca and Oxford University have reduced the spread of coronavirus. According to a study by two institutions that has not yet been verified by independent scientists, surveillance of vaccinators shows that their ability to infect is significantly reduced. Equally striking is another result: by separating the first and second administration by three months, the effectiveness of vaccination is maintained within the interval. The study came in the same week, when many European countries were studying not giving the compound to people over the age of 65.
Researchers at Oxford University and pharmaceutical companies have released the latest results of four studies they are conducting (two in the UK and one in Brazil and South Africa). This work adds one month’s data to the data already published in November last year, and details the new data observed over time.
Perhaps the most prominent is the effect of the vaccine on the ability of the virus to maintain its infectivity. Based on weekly monitoring of samples from British volunteers, the authors believe that the possibility of coronavirus transmission has been reduced by 67% after the first administration. This series of trials is not intended to measure the impact of the vaccine on the spread of the virus. But weekly tracking of participants allows us to estimate that. In principle, an effective vaccine should reduce the severity of infection or make it asymptomatic, but not change the PCR positive rate. But what they repeated weekly was a 67% decrease in positive CRP after the first dose and almost 50% after the second.
“We don’t measure a particular mode of transmission because it requires a different kind of research. What we got was a study that showed the number of people who were no longer infected. Andrew Pollard, a scientist in charge of vaccine research at Oxford University, said that if they did not, they would no longer be able to transmit the virus.
“We now know that the Oxford vaccine can also reduce transmission, which will help us all out of this epidemic,” Matt Hancock, the British government’s health minister, told the BBC, the New York Times reported.
Another result of the study, being reviewed in the medical journal Lancet, is related to the interval between doses. When moving from the experimental phase to the widespread use of vaccines already on the market, it is recommended that the interval between two punctures be about three weeks. The time interval used in the experiment seems to be the right time to activate the defense of the immune system, rather than too long, so that the virus cannot find a way to escape through selective pressure.
But here science stumbles on public health policy. Encouraged by some very preliminary results, the British authorities (and then the authorities of other countries) decided to interval the second dose more than 21 days in order to provide more vials for the first dose. This decision involves its risk, because it can promote the mutation of the virus by finding weak links in the immune system. In any case, the World Health Organization recommends no more than six weeks.
The Oxford and AstraZeneca studies found a problem: they couldn’t produce all the vaccines they needed to follow the initial two dose plan. So they extended the second dose to a subgroup of volunteers. They turned the problem into an opportunity to verify the dose interval.
Their results suggest that the effectiveness of the vaccine will improve over time. They showed that when the interval between the first and second administration was less than 6 weeks, the proportion increased from 54.9% to 82.4% at 12 weeks. This temporary separation allowed them to determine that the protection rate for people who received only one dose of the vaccine remained at 76% within 90 days, a decrease of only 6 percentage points compared with the double dose regimen.
“These new data provide important validation of provisional data used by more than 25 regulators, including MHRA and EMA (the UK and the European Organization for drugs, respectively) to grant emergency use of vaccines,” Professor Pollard said in a statement
The British scientist, co-author of the study, also said that his findings support the British authorities’ recommendation that the two doses should be separated so that more people can get the vaccine available, “Confirm that people are protected from the single dose vaccine for 22 days.” But they also acknowledge that more research is needed to determine whether there are long-term immune differences between injections or between injections.
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