Health Notice: “Evidence increases that Ómicron escapes the immunity of the vaccine”

The arrival of the Omicron variant it has once again raised alert levels for the pandemic around the world. First detected in South Africa, and subsequently relocated a few days earlier in Netherlands, this variant has the peculiarity of having up to 32 mutations in the spike protein, the one used by most vaccines to combat them.

Therefore, one of the main concerns of the experts is how it will affect these COVID serums. The first data from a study of the South Africa Genome Surveillance Network (NGS-SA) indicate that they ensure to a high degree that it is achieved avoid a serious picture of the disease and possible hospitalization.

Now him Ministry of Health of Spain, in its latest update of the Rapid risk assessment of the Omicron variant, warns that “evidence increases that escapes the immune response caused by previous variants and by vaccines“. In said report, the fact of the numerous cases detected in Europe between November 26 and December 2.

“111 cases have been confirmed in 16 countries of the European Economic Area: Austria (5), Belgium (4), Czech Republic (1), Denmark (14), Finland (1), France (9, including 1 in Reunion), Germany (13), Greece (1), Iceland (1), Ireland (1), Italy (9), Netherlands (16), Norway (5), Portugal (19), Spain (6) and Sweden (6)Likewise, cases of this variant have been reported in a total of 35 countries outside the European environment, among which are Australia, Brazil, Canada, India, Israel, Japan, Malaysia, Botswana or South Korea.

Variant “more divergent”

The report, signed by the Center for the Coordination of Health Alerts and Emergencies (CCAES), points out that this variant, Ómicron, is the “most genetically divergent of those that have been detected during the pandemic, raising great concern that it may be associated with a significant reduction in the effectiveness of the vaccine and an increased risk of reinfections“.

In turn, they point out that “several” of these changes in the sequence that encodes the spike protein of this variant have been previously described, and are “associated with immune escape of neutralizing antibodies or other properties“. In this regard, they comment on the example of a variant previously described, with up to 20 mutations in the same protein (32 have Omicron), and which was then associated with “a almost complete leak from neutralization by convalescent and vaccinated sera “.

Thus, they emphasize, “as Ómicron still carries more mutations in the S gene compared to the synthetic variant, a very significant effect on neutralization is expected “, warn CCAES experts.

The role of T cells

On the other hand, they consider that “the potential for immunological escape from non-neutralizing antibodies and purpose T from memory targeting non-surface proteins is more difficult to determine. “In this way, and as has been proven in various studies, vaccines increase patients’ T cells, with which the virus is faced, so it could have an immunity different from that of antibodies.

“Memory T-cell responses may offer a route to long-lasting immunity and protection against the development of serious disease, even in situations in which the evolution of the virus leads to spike protein mutations that escape pre-existing neutralizing antibodies “, they detail.

Risks and severity of those affected

The rapid advance of the variant in many countries of the world, they point out, is associated with “a decrease in the risk of primary infection and an increased risk of reinfection“Something that, if confirmed,” would have important implications for the public health planning“.

Finally, Health details that the cases detected in Europe are, for the most part, mild in nature. “Half of the cases were asymptomatic and the other half presented mild symptoms”, while no serious cases, hospitalizations or deaths associated with Omicron have been reported. In any case, the Ministry asks for prudence because the cases are, at the moment, few and very recent. “Serious results often take several weeks to be seen and more time to be evident at the population level, which would affect hospital occupancy rates“. Of the registered cases, they point out,” the majority are young or middle-aged people and they were fully vaccinated“.

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