How does the Delta variant affect me?

Despite advances in immunization, the pandemic continues to hit hard. The appearance of new mutations of the Wuhan coronavirus This puts us in check and there is even talk of a third wave. The Delta variant he has become the enemy to be avoided. To this end, several measures have been taken, among which the entry of Argentines into the country from abroad has been restricted. However, experts agree that it will surely be possible to delay its spread. but don’t stop it.

Given this premise, many wonder how protected are we In front of her. It was already expected that complete immunization schedules this is the key to fighting it but what we know about those who have already had the disease. Are there any risks of re-infection with Delta? What is the power of natural immunity on this variant?

“In general, the convalescent plasma infected with the Wuhan strain have almost three times less neutralization capacity when he meets Delta. In other words, the natural immunity generated by a person infected with the original variant decreases in the face of these mutations and, therefore, increase the chances of re-infectionSays Conicet biochemist and principal investigator Jorge Quarleri.

These possibilities of reinfection “are even older whether the recovered person was first infected with the variants Beta (South Africa) or Gamma (Manaus)“, Says Quarleri, from a study published two weeks ago in the scientific journal Cell.

The Delta variant is characterized by evading the immune system and having a high transmissibility capacity. “From the mutations that generate worrying or interesting variants, the virus changes its face so that the immune system does not detect it so easily”, explains the biochemist.

“The most significant changes are seen in RBD, which is a receptor binding domain found in S protein. When the virus mutates, it changes the combination of this ‘key’ with which it will attempt to enter cells. of our organism.. Although these modifications will cost more to open the lock, at the same time, will save time to do it because it will go unnoticed, ”he adds.

He ensures that the data is lacking to know what the impact of this recontagion may be. “In the vast majority of cases of respiratory viral infections when they occur re-infections usually have a sweeter course. There is a certain cellular response, our body recognizes small parts of the virus and this allows it to react quickly. Even though the virus has had cosmetic surgery, it remains there something familiar, ”he adds.

For the moment, we are not talking about a greater virulence in the tables. Yes, more cases of hospitalization in patients at risk. “The Delta variant has almost twice as likely to be hospitalized than Alfa (United Kingdom), especially among those who co-morbidities. This shows a different behavior of the virus, “warns Quarleri, citing Scottish research published in the medical journal. The Lancet.

The trace of the first contagion

Lautaro de Vedia, an infectologist at Muñiz Hospital and former president of the Argentinian Society of Infectious Diseases (SADI), agrees that “the reinfection is likely to be less serious”, adding: “It has to do with the person who has already had the disease starts from a certain level of antibodies. While not as effective against Delta, they do add up. It’s better than nothing”.

Another element to take into consideration, according to De Vedia is how did the first infection go?: “It’s not the same if the person experienced it asymptomatically or with a stronger image. Nail greater extent in the development of the disease, that is to say that having had more symptoms usually results in a more robust immune response that it will leave the immune system with more resources in the face of reinfection, ”underlines the former president of SADI.

Along the same lines, he argues that “if our body detects and attacks the virus faster the risk of complications should be lower”.

In turn, he asserts that, in practice, “having had the infection is comparable to having received a dose of vaccine”.

“Therefore, those who applied a single dose but who already had the Covid have a similar or even higher level of protection than those who added the two doses but did not experience the disease,” he underlines.

In order to Eduardo López, infectologist at Gutiérrez hospital and member of the committee advising the president, “the Delta variant is very young, so there is no clear data yet on the effects of acquired immunity after infection,” he says .

“We know from recent studies that vaccinated individuals have increased immune defenses than those who have known only the disease, ”explains López.

And he specifies that he refers to the vaccinated with the complete diagram, taking into account that “for strains which escape the immune system both doses are needed”.

“However, in all the cases studied, slightly decreases the percentage of antibody activity neutralizers provided by vaccines against Delta», López contributes.

He says that so far there is research from Pfizer regarding Delta that shows a 88% effective with two doses. And that the Gamaleya Institute said that with Sputnik V they reached similar percentages. “We do not have details on the effectiveness of Sinopharm against this worrisome variant and there are no conclusive data on AstraZeneca,” he adds.

It also highlights the high transmissibility of Delta. “It is 40% to 80% more contagious than the Alpha variant, from the UK, which was already spreading the virus 30% more than the original, ”says López.

So far they have been detected five cases of travelers who entered the country, tested positive and later it was learned that they had been infected with the Delta variant.

MG