The World Health Organization Strategic Advisory Group of Experts on Immunisation (SAGE) has recommended the vaccine developed by AstraZeneca and the University of Oxford against COVID-19 for people over 18 years of age, including those who are over 65 years, in contrast to the recent decisions of some countries, including Spain, who are restricting its use to senior citizens.
They have also given the green light to its use against all variants of the virus, despite the fact that South Africa has stopped vaccinating with the AstraZeneca vaccine.
In its report, SAGE acknowledges that preliminary analyses have shown a “slight reduction” in the efficacy of this vaccine against the British variant, as well as a “marked reduction” in efficacy against mild and moderate disease due to the South African strain. .
“In view of this, WHO currently recommends the use of the vaccine according to the prioritisation roadmap, even if there are variants in a country. Countries should carry out a benefit-risk assessment according to the local epidemiological situation, including the spread of circulating virus variants.
These preliminary results highlight the urgent need for a coordinated approach to surveillance and evaluation of variants and their potential impact on vaccine efficacy. The WHO will continue to monitor the situation; As new data becomes available, the recommendations will be updated accordingly, “the text states.
“Even if there are variants in a country, there is no reason not to use the AstraZeneca vaccine against COVID-19 in order to reduce severe disease among this population. In South Africa, there is a marked reduction in the effectiveness of the vaccine against mild disease and moderate and reduction in antibodies.
Efficacy against severe disease has not been evaluated, but there is indirect evidence that it continues to be effective “, SAGE’s top leader, Alejandro Cravioto, highlighted at a press conference from Geneva (Switzerland).
“The South African trial was very small. It was not studied whether the AstraZeneca vaccine is effective against severe COVID-19, hospitalisation and deaths. That is the most important thing. We think that it is effective, but we do not have the evidence.” added the director of vaccines of the WHO, Kate O’Brien, who has pointed out, however, that it is likely to be more effective in severe cases because “all vaccines are more effective against severe disease”.
WHO chief scientist Soumya Swaminathan has said that for countries that have not yet started vaccinating with these doses, initiating vaccination would mean that the “benefits far outweigh the risks”, even in countries where there are circulating variants.
ALSO FOR OLDER PEOPLE
On the limitation of age, the United Nations international health body recognises that because a relatively small number of participants aged 65 years or older were recruited in clinical trials, there were “few cases of COVID-19 in both the vaccine and in the control group in this age category, and therefore the confidence interval in the estimate of efficacy is very wide.”
However, they highlight that vaccine-induced immune responses in older people are “well documented and similar to those in other age groups.” “This suggests that the vaccine is likely to be effective in older people. Taking into account the totality of the available evidence, the WHO recommends the use of the vaccine in people 65 years of age or older, “the text states, although it recognises the” limitation “in the scientific evidence. “The vaccine can be administered from 18 years of age, with no maximum age limit, so it can also be administered to people over 65 years of age. The results in these people are no different than in younger groups,” Cravioto said.
The AstraZeneca recommended regimen is two doses (0.5 ml) administered intramuscularly into the deltoid muscle. Depending on the manufacturer’s product label, the vaccine can be given 4 to 12 weeks apart. In any case, and “in light of the observation that the efficacy and immunogenicity of the two doses increase with a longer interval between them”, the WHO recommends an interval of 8 to 12 weeks between doses.
“If the second dose is inadvertently given less than 4 weeks after the first, there is no need to repeat the dose. If the second dose is inadvertently delayed for more than 12 weeks, it should be given as soon as possible. It is recommended that all vaccinated people receive two doses “, according to the WHO.
IN PREGNANT, BUT ONLY AT RISK
WHO has given the go-ahead for both pregnant and lactating women to receive the vaccine, as long as the benefits do not outweigh the risks and are between risk groups? “In the absence of clinical trials, a general vaccine recommendation is not issued for pregnant and lactating women, but it is recommended if these women are among the risk groups,” Cravioto highlighted.