Older adults wait their turn to receive the Chinese Sinovac vaccine against covid-19 today, during a mass vaccination day for people over the age of 70, at the Pontificia Universidad Católica Madre y Maestra, in Santo Domingo, Dominican Republic. The Dominican Republic is currently implementing the first phase of the national vaccination plan to prevent covid-19, which was reinforced last week with the arrival of 768,000 doses of the Chinese vaccine Sinovac. EFE/ Orlando Barría
The new variant of COVID-19 identified as omicron is once again putting the world on alert. With countries in the middle of the vaccination and reopening phase, many have found it necessary to close their borders again.
In addition to this, there is little information available on this variant and the high possibility of reinfection and spread.
Given this reality, Robert Paulino, former scientific director of the Emergency and Health Management Committee of COVID-19, answers basic questions about the country’s expectations regarding the imminent arrival of the omicron variant in December, the month of the Christmas holidays.
Why are variants appearing?
The appearance of new variants of COVID-19, or Sars2, which is the virus that causes COVID-19, was to be expected. The variants arise precisely because we have populations that do not have neutralizing antibodies generated by vaccines. And for that reason we still have disparities: regions where the percentage of vaccination coverage is very low.
It is estimated that every 14 days, which is known as the virological cycle, two mutations will appear in each virus. Therefore, the greater the transmissibility generated, the more mutations will appear.
What happens with Omicron and why is it classified as a variant of concern?
It is classified as a variant of concern because it has an accumulation of mutations that may have occurred due to three particular situations.
One, because it has generated a constant transmission without any type of community control by circulating antibodies of importance. Second, because we know today that there are populations that can generate chronic infections and be positive for months, and each 14-day cycle generates and accumulates new mutations. And thirdly, the virus has been selecting mutations that facilitate its transmissibility. Therefore, what we are looking for and what we are seeing is that it increases its transmissibility.
Can people who have been vaccinated become infected with omicron and develop severe clinical manifestations?
Theoretically that could be possible. However, in real life, when we expose a virus to a given population dynamic, that changes a lot because it depends on the percentage of vaccination coverage that a population is going to have. This is known as the ‘cushion effect’, which means that the more people are vaccinated, the more evolutionary brake a virus will have to continue multiplying. That is why it is so important that people understand that the vaccination process is not personal, but communal.
Does the Dominican Republic have enough cushion effect to face Omicron?
Not yet. We still have a 40% of the population that has not been vaccinated and that is a big challenge because it is very similar to the situation in other countries, it is not a challenge specific to the Dominican Republic, it is something that has happened in other countries as well. However, what have we seen in countries with high coverage? That there have been no appearances of variants of high concern because the brake generated at the community level by such a high percentage of vaccinated people does not allow genetic diversity in the virus to occur.
This phase of the pandemic has been characterized as a pandemic of the unvaccinated. The people who are getting sick and who are coming into intensive care units and who are dying are unvaccinated people.
If vaccines don’t prevent people from getting infected, what is the benefit of using vaccines?
The benefit is simple. First, vaccines create an evolutionary brake on the virus. Therefore, if you have a very high population of vaccinated people, the viral particles of the people who become infected and who have already been fully vaccinated are going to be lower. Therefore, their transmissibility rate is lower. In people who are not vaccinated, the transmissibility rate is higher. And the higher the transmissibility rate, the higher the mutation rate. The higher the mutation rate, the more variants.
