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Are Delta Variant Vaccines Effective?

Posted: Monday June 21 2021 8:52 AM

The delta variant, first discovered in India, continues to expand in Spain. Now, according to the latest Health report, which analyzes the evolution of new strains of coronavirus (dated June 14), this is a mutation that “began to appear in screening over the past 4 weeks” , but with values ​​less than 1%.

That is to say, the data in the report is in the same line as what the director of CCAES, Fernando Simón, exposes, which underlines that “it does not have an important space”. However, the same report warns that it is still unclear what the extent of this mutation (already predominant in the United Kingdom) may be. In addition, it leaves three substantial alerts: “Probable increase in transmissibility. Possible increase in severity. Slight decrease in vaccine efficacy.

This last point is one of those which have worried the international bodies the most in recent months. While vaccines have already been able to cope with extremely transmissible variants, such as the chaos of the UK native Alpha strain, Delta still casts doubt on its ability to dodge the antidote. Although several experts call for tranquility: the key would lie in reaching the full guideline.

Pfizer and AstraZeneca safe against mutations

According to Ignacio López-Goñi, a microbiologist at the University of Navarre consulted by the EFE agency, data from British public health indicate that the delta variant has “some loophole for neutralizing antibodies at an experimental level, and less effectiveness with one dose of vaccine. “Although the expert underlines this nuance: less effectiveness in a single dose. Not in two.

In this sense, according to López-Goñi, the two doses of Pfizer or AstraZeneca are “sufficiently effective to control this variant, provide a good immune response and are effective in preventing hospitalization”. But, knowing these data, why is this variant so prevalent in a country like the UK, where vaccination has progressed more than anywhere else in Europe?

Here again, as experts, including Federico Martinón-Torres, member of the World Health Organization (WHO) Vaccine Advisory Committee in Europe, it is true that the British country has made great strides in the area of ​​vaccination. , but his strategy focused on vaccinating as many people as possible with a single dose, which does not offer complete protection, and using the longest recommended interval for the second.

Urgency to advance full vaccination

In view of this, both López-Goñi and Martinón Torres, in order to avoid a significant rebound in infections in our country, “the most important thing is to finish, as soon as possible, this second dose in the first groups”.

As they explain, everything indicates that the delta variant seems more transmissible, although this does not depend solely on the microorganism, because “there are a lot of other factors,” says the WHO adviser. “The most that has been shown, accepted by the scientific community, is a slight increase in transmission capacity, of the order of 30%.”

From what “there is no proof yet” is that it is associated with greater severity of the disease, explains López-Goñi, and explains that this variant, classified as “worrying” by the WHO, has thirteen mutations, three of which has the possible increase in infectivity is linked.

For its part, the WHO has admitted some evidence of an immune leak of the delta variant, that is to say that it could have an impact on the protective capacity of vaccines. But López Goñi calls for tranquility: the probability that a variant will escape vaccines completely is “very low”. However, recalls the expert, “it is not impossible, so you have to be vigilant.

“There will be no strain which, after passing the infection or having been vaccinated,” suddenly returns to zero point, “adds Martinón Torres. Thus, as he explains, there are mechanisms of immunity in the body that “keep you from going unattended when faced with a new variant. “However, according to the doctor, the British decision to delay the lifting of the measures can be seen as” a warning to sailors. “This is, at other times, what happened there, he anticipated what could happen here,” he concludes.

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