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Omicron variant – The effectiveness of vaccines against the new strain

The appearance of the new omicron strain in South Africa, its high transmissibility, the large number of mutations and its rapid spread around the world have particularly worried scientists globally.

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Data on the effectiveness of available vaccines are still early.

The Doctors of the Therapeutic Clinic of the Medical School of the National and Kapodistrian Athens Theodora Psaltopoulou, Panos Malandrakis, Giannis Danasis and Thanos Dimopoulos summarize three recent relevant publications in the prestigious international journal Nature.

Multiple mutations (37 to 15 in the spike region of the virus) of the strain in the spike region of the virus raise concerns about whether existing vaccines provide effective immunity to Omicron.

A study (doi: https://doi.org/10.1038/d41586-021-03826-3) showed that the new strain is resistant to the serum neutralization of people who had been ill, as well as the serum of people who had been vaccinated with one of the approved vaccines.

Even serum from subjects receiving booster doses had reduced neutralizing ability against the Omicron strain.

As for monoclonal antibodies, their effectiveness against the new strain is reduced, even those that have already been approved and administered.

Another study (doi: https://doi.org/10.1038/d41586-021-03824-5) after sequencing of the gene of the Omicron strain showed that it also requires the ACE2 receptor to infect human cells.

In serum samples from persons that were both vaccinated and fallen ill and those vaccinated alone, the neutralization of the Omicron strain provided by the vaccines was 22 times less than that of the original Wuhan strain.

In individuals who had become ill and received two doses of vaccine, the neutralization of the Omicron strain was equivalent to the neutralization provided only by the vaccine without a history of disease compared to the original strain of the virus.

Decreased immunity due to Omicron

In conclusion, this study concludes that although the immunity provided by vaccines is reduced, they certainly provide some protection especially with booster doses.

A third study (doi: https://doi.org/10.1038/d41586-021-03825-4), also published in the journal Nature, confirmed reduced efficacy against the Omicron variant, possibly exceeding the third dose.

Antibodies against the RBM region lost their  in vitro potency for the Omicron strain, with only 3 of 29 retaining their efficacy (including ACE-2 mimetic antibody S2K146). Also other antibodies that do not target RBM were effective against the Omicron such as sotrovimab, SX259 and S2H97.

The escape of the micron strain from antibody protection is a key antigenic change in the evolutionary course of the SARS-CoV-2 virus. Therefore, it is particularly important to administer the third booster dose in conjunction with known protective measures, in order to limit the spread of the Omicront strain and in particular to prevent disease from it.

  • Published in Health

Univ. Prof. Vasilakopoulos: Herd immunity -without vaccination- presupposes 4 million infections

Professor of Pulmonology and Intensive Care, Theodoros Vasilakopoulos, made the nightmarish estimate that if the vaccinations do not proceed, 4 million people will need to get sick in order to achieve immunity of the herd.

As he noted, if the population is not vaccinated, in order to reach immunity of the herd, out of the 5 million Greeks who have been left unvaccinated, 3.5-4 million people will be infected.

"But this will have a cost in the loss of human life and the NSS will not be able to bear it. "99% of coronavirus deaths could be prevented by vaccination."

An infection explosion in the near future

Mr. Vasilakopoulos, warned, speaking to Sky, that we will have an outbreak of cases in the near future, emphasizing that there is no safe way to restart without vaccination.

"The theory that we can open with strict protocols does not exist. With current vaccination rates, the number of daily cases will be very high. Given that the Delta strain that will prevail is 60% more contagious, we must be 60% more vaccinated and 60% more careful", said Mr. Vasilakopoulos, reminding that in 15 days out of 500 cases we reached 3,500.

Responding to those who refuse to get the vaccine because they are afraid of the long-term consequences on the grounds that it has not been tested for a long time, he noted that with the vaccine it is exposed to the spike protein. That is, if he gets sick, he is not afraid of the consequences of exposure to the proteins of the virus and with the vaccine that the exposure is lower than he is in a natural infection, is he afraid?", He noted.

For the Guillain-Barré syndrome associated with the Johnson & Johnson vaccine, the professor said that one is a thousand times more likely to develop it if the virus is transmitted.

Vaccinated people are much less likely to transmit the virus

Asked if the vaccinated person could transmit the virus, he explained that the chances were much lower. "I have little chance of having the virus inside me. And when I have it, I have it in such a concentration that it is much smaller than I would have it if I were unvaccinated. So the chance of transmitting it is much lower. I can not say that there is no chance, but it is so small that it is not a problem."

Regarding the possibility of serious illness, Mr. Vasilakopoulos pointed out that it is minimal and mainly concerns people who despite the vaccine did not have a good immune response, because they were taking drugs that prevented the immune system from reacting well, such as transplant recipients, people with rheumatism and cancer patients who are immunosuppressed.

On the vaccination of minors

Regarding the vaccination of children, he said that children in the US are being vaccinated en masse, pointing out that parents should stop seeing the vaccine as taboo. "Children are very unlikely to get seriously ill and lose their lives. However, we have lost three children under the age of 18 in Greece so far and many more have been admitted to the ICU. Imagine a child alone for 10 days in a Unit, without his parents", he added.

Finally, regarding the possibility of a new lockdown, he stressed that the country can not close because some do not want to be vaccinated. "If the situation worsens, the solution is to drastically limit the activities of the unvaccinated. In summer they can make use of mixed outdoor spaces. In winter when the temperature drops, what will happen? Will they allow them in a restaurant? He will stay at home," he concluded.

  • Published in Greece
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