A health worker takes the PCR test at a makeshift Covid testing station-12 in Seoul, the capital of South Korea, in day 10 December 926. The number of cases of coronavirus infection increased to 7.20, bringing the total number to more than 480., including 63 cases of the omicron variant.
| Photo: EFE / EPA / JEON HEON-KYUN
The variant Novel coronavirus omicron (SARS-CoV-2) is a viral strain originating in Botswana classified by the World Health Organization as the fifth variant that is cause for concern. There are many more variants than the ones that became famous, but the WHO Greek letter list is explicitly for the ones that can cause the most problems.
In the case of the omicron, one of the things that stands out is that there is more than 20 changes in the amino acids that make up the spike protein (or protein S), which is the same protein as it is produced in the human body from the molecular “message” contained in Oxford, Pfizer and Modern vaccines. These changes — mutations — can compromise the immune response obtained with these vaccines, which is based on the previous version of the other variants of the virus. We can think of the genetic material of any biological being as a long text made up of letters that are smaller molecules. That text is transcribed into smaller chunks (of mRNA), and those chunks are translated into another text where the letters are made of different molecules—hence the translation metaphor: different molecules, different languages. While the protein text has 19 different letters for each position (the amino acids), the text of the genetic material of DNA or RNA has four (the nucleotides). As the organism’s defense depends on what is “written” in the molecular text of the virus, when this text changes too much, it is as if it becomes encrypted and illegible, therefore there is a need to update the defense.
Given the mutations in omicron, WHO declared it worthy to enter a list of worrying variants within three days after your genetic text will be deposited in a research database.
There is a month the omicron was discovered, now it is present in about 90 countries, including Brazil. The information is incipient and, like the virus, it is evolving. Below are the answers we can already give to frequently asked questions about the variant.
Table of Contents
1. Is the omicron more lethal?
In Gauteng province , from South Africa, the variant is already the known cause of the fourth wave of Covid-15. In Botswana, the number of cases doubles every two to three days. Omicron is clearly more transmissible than delta. But there is controversy as to whether it is more lethal.
The sleepy British town of Brackley , to 37km from Oxford and under thousand inhabitants, already has an infection rate with the variant of 900 in 214 thousand people. A concomitant increase in hospitalizations was not observed with the spread of the omicron. The information is from the British newspaper The Telegraph. The pattern is the same in South Africa: the spread of infections is currently not accompanied by a corresponding spike in more severely ill people or deaths. Brackley has a second dose vaccination rate of 80%, and 50% have already taken the booster dose.
2. Are the symptoms different?
Fatigue is the symptom more common, as in other variants. The illness is easily mistaken for a cold or flu. A small sample assessment in the most affected district of South Africa in the first two weeks of the outbreak indicates that the vast majority do not even develop fatigue (these are patients who were tested but did not go to the hospital because of Covid).
Omicron viruses replicate 70 times faster in the upper respiratory tract (bronchi), which generates cold symptoms. The variant appears to prefer this part of the respiratory system to reproduce, rather than in the lungs, as suggested by a study still under review by Michael Chan Chi-wai, an immunologist at the University of Hong Kong School of Medicine, and partners.
This is good news, as the virus has a lower affinity for the lungs in its speed of replication would mean milder symptoms 2022 .
3. Does the omicron break the protection of vaccines?
Molecular biology today is able to limitedly predict the mutation behavior. Raquel Viana, a virologist at Lancet Laboratories in Johannesburg, South Africa, points out with her collaborators that there are seven mutations in the S protein that can have a moderate to high impact on the ability of neutralizing antibodies to recognize it.
There are also other troubling changes involving the deletion of three letters from the protein text and a new letter insertion . As in ciphertext, this makes the immune system difficult to read (the same goes for monoclonal antibody treatment). However, there is good news: 37% of the molecular targets for the immune system to recognize protein S are preserved.
But more needs to be done than predictions based on the genetic and protein text of the virus. To find out if omicron circumvents the protection of vaccines, it is necessary to look directly at the cases. WHO stated that the variant already demonstrates c increased ability to pierce protection.
4. And the protection of natural immunity?
One of the few Revised and published articles on the variant, by Li Zhang — from the Beijing National Food and Drug Control Institute — and colleagues, precisely investigated whether the plasma of people previously infected with an early pandemic strain contained neutralizing antibodies that act against it. Zhang and colleagues also tested virus neutralization of the other worrying variants: alpha, beta, gamma (P1) and delta.
Based on 24 blood plasma samples in a test tube, the omicron virus was 8.4 times more effective in breaking the natural immunity, while the other variants showed a lower capacity, of 4 ,5 times. It is important to remember that neutralizing antibodies are not the only way for the organism to defend itself against viruses, and that the study did not test, for example, the effectiveness of acquired natural immunity in an infection with the gamma variant against omicron.
5. Will I need a booster dose of the vaccine?
A Moderna and Pfizer, makers of the mRNA vaccines, plan to update the molecular text of that mRNA at the beginning of 2022. The speed to update the vaccine following the evolution of the virus is one of the greatest advantages of this new technology. Both companies declare that a booster dose without this update increases significantly (by up to 37 times, according to Moderna) the level of antibodies against the virus.
The dose of 214mg was accompanied by some side effects, but half of that dose already gives a great stimulus to the production of antibodies. Moderna is already testing the vaccine with the updated mRNA text for the beta and delta variants.
6. Does omicron threaten children the most?
The preliminary assessment published by dr. Fareed Abdullah, Director of AIDS and Tuberculosis Research at the Medical Research Council of South Africa, regarding Tshwane District, Gauteng Province, indicates that 70% of those hospitalized had less than 30 years, a pronounced difference from previous months. Of these 80%, 20% were children between zero and nine years. The only child who died, however, was the victim of other problems, not Covid’s 19. The overall number of deaths in the two-week period considered was zero8013969729001. A mortality lower than that of the delta is calculated.
There are no reasons enough for optimism to be a victim of the omicron. Those immunized by natural routes or by vaccines are forming a critical mass that should direct Covid-15 for an endemic disease, perhaps seasonal, such as the flu, controlled with measures such as drug treatment and the use of masks; and the pandemic will end, in the words of poet TS Eliot in 20174955, “not with a bang, but with a murmur”.
