Third doses of COVID vaccines in Argentina: who receives them and which vaccines are used

A third dose of the coronavirus vaccine has already started to be applied in Argentina (EFE / Etienne Laurent)
A third dose of the coronavirus vaccine has already started to be applied in Argentina (EFE / Etienne Laurent)

The health decision became known a week ago, and today it is a reality in almost every province and city of Buenos Aires. ONE third dose of the vaccine against coronavirus those over 50 who have received Sinopharm and people over 3 years who are immunocompromised who have started the vaccination plan with any component.

The decision was made on the basis of recommendations from the WHO and international organizations: “The evidence shows that it is possible to progression in immunocompromised individuals who have low defense for some reason, older than 3 years, who have received any vaccination scheme. We will work on planning and distribution with each of the provinces “, explained the Minister of Health, Carla vizzotti. These two groups consist of approximately 1.6 million people.

The official further clarified this a third dose is not the same as a booster: “The third dose supplements the primary system to extend protection and enhancement after receiving the recommended primary system, what it does is strengthen the immunity periodically and it is at least 6 months after receiving the primary system”.

It will be for those over 50 who have received Sinopharm and people over 3 years who are immunocompromised who have started the vaccination scheme with any component.  (EFE / Sergio Cañizares)
It will be for those over 50 who have received Sinopharm and for people over 3 years who are immunocompromised who have started the vaccination scheme with any component. (EFE / Sergio Cañizares)

In addition to the decline in the effectiveness of vaccines, the third dose serves to increase the immune response in people with immunodeficiency or with immune changes naturally associated with aging (immunosenescence). It also serves to reduce the effect of COVID-19 mortality in people over 50 and before progress variant Delta and community broadcasting.

In accordance with international recommendations and some clinical studies conducted in the country The National Immunization Commission (Conain) advised the Ministry of Health of the Nation in the decision to add one more dose to the homologous or combined schemes of these two groups, according to some set parameters.

– Third dose for people over 50 years

“On those over 50, a further heterologous dose will be prioritized, for which the use of a non-replicative virus vaccine is recommended [AstraZeneca, Sputnik V y CanSino comparten esa plataforma] subject to availability, conditions that facilitate rapid decentralization and access, in order to cover the entire population with an extended scheme in the shortest possible time ”, states the document prepared by the Directorate for Control of Immune Preventable Diseases.

The official recommendation for this group is one dose of AstraZeneca. “The minimum interval for application of the additional dose will not be less than 4 weeks from the last dose of the primary program,” the recommendation continues.

A minor receives a dose of the COVID-19 vaccine.  EFE / Carlos Ortega
A minor receives a dose of the COVID-19 vaccine. EFE / Carlos Ortega

– Immunocompromised vaccines

The decision to vaccinate immunocompromised individuals with a third dose was supported by several clinical trials conducted in the country who assessed the protection of COVID-19 vaccines in transplant recipients, who have been among priority groups in access to immunization.

People who require solid organ transplants are immunosuppressed before the transplant procedure. After transplantation, this condition is exacerbated by pharmacological immunosuppression to prevent and treat graft rejection and by the immune mechanisms that cause it. It is this situation that makes them less responsive to vaccines, but their vulnerability marks the importance of being vaccinated. For this reason, the importance of the extra dose in transplant patients is emphasized, ”he explained Infobae the doctor Daniela hozbor, researcher at the Department of Biochemistry and Molecular Biology, dependent on the Department of Biological Sciences at the Faculty of Exact Sciences at the National University of La Plata and Conicet.

“When analyzing these results on humoral response, it is suggested transplant recipients should be among the priority groups to receive booster dose, ”He pointed out Infobae the doctor Rolig biglione, researcher at Conicet.

The decision to vaccinate immunocompromised individuals with a third dose was supported by several clinical trials conducted in the country (EFE / José Jácome)
The decision to vaccinate immunocompromised individuals with a third dose was supported by several clinical trials conducted in the country (EFE / José Jácome)

Thus vaccines as a third dose approved for those immunocompromised vary by age. Will apply “those undergoing cancer treatment for solid blood tumors, those transplanted under immunosuppressive therapy, “People who have had a haematopoietic stem cell transplant within the last two years, or who are immunosuppressed, patients with moderate or severe primary immunodeficiency, people with HIV and those who are being treated with high doses of corticosteroids or immunosuppressants”, reads the Minister’s setting.

To older than 18, who have already used a complete form of Sputnik, AstraZeneca and Sinopharm or the combination of Sputnik with AstraZeneca or a dose of an mRNA vaccine (Pfizer or Moderna), they will receive a new dose of the first component of Sputnik V or a dose of AstraZeneca if they are between 18 and 39 years old or only AstraZeneca if they are over 40 years old.

In it minors between 3 and 11, it was stated to complete the Sinopharm scheme with a third dose of the same brand, and in minors between 12 and 17 years of age, the two-dose mRNA scheme will be completed with another dose from the same platform. The interval for receiving the new dose is the same as for the other group. The indication for this third application is independent of the booster dose for the general population that can be announced from December.

The measure also serves to reduce the impact of COVID-19 mortality in people over 50 and in the light of the advances of the Delta variant in community transfer.  (EFE / Rayner Peña R)
The measure also serves to reduce the impact of COVID-19 mortality in people over 50 and in the light of the advances of the Delta variant in community transfer. (EFE / Rayner Peña R)

Is it safe to combine?

There are several studies worldwide that are being done on combination of vaccines. Months ago, they were published as a study still under peer review in the journal The Lancet the results of the combination of the messenger RNA vaccine, produced by the companies Pfizer and BioNTec, with the vaccine developed by the University of Oxford with the company AstraZeneca. This is the CombivacS study, which was conducted in Spain. A combined vaccination program with a second dose of the Pfizer / BioNtech vaccine (called Comirnaty) is being evaluated in individuals under 60 years of age who have received a first dose of AstraZeneca (Vaxzevria). They already have the first results of cellular immunity.

And a recent study presented to the CDC on Friday that tracked individuals who received combined boosters did not report any serious side effects related to the vaccines. But experts also point it out combination vaccine data are limited to a small number of persons, especially compared to the much larger studies that have shown that each of the vaccines is safe and effective alone.

View of a Chinese vaccine against covid-19 from Sinopharm in a file image (EFE / Shahzaib Akber)
View of a Chinese vaccine against covid-19 from Sinopharm in a file image (EFE / Shahzaib Akber)

Allowing people to get any vaccine as a booster can be a boon for people who are anxious for an extra shot. “The future would be to combine vaccines for COVID-19 based on different platforms and even combinations of vaccines based on the same platform would be made“, Held Angela Gentile, a vaccine specialist from the Argentine Society of Pediatrics and the National Commission on Vaccine Safety. “If coronavirus becomes an endemic like the flu every year, there is a possibility that different doses of vaccines will have to be combined. Humanity today needs to both combine vaccines and have multiple doses in connection with a tragic and surprising pandemic,” he said. .

Any booster shot, even if it’s the same as your first shot, will increase the amount of antibodies that can fight coronavirus.. But in some cases, mixing vaccines can provide better protection, experts say. Early data have shown that after an initial dose of Johnson & Johnson with an mRNA vaccine, Moderna or Pfizer produced significantly higher levels of neutralizing antibodies.

Why are reinforcements effective?

A third dose gives another signal to the immune system to complete its response (Getty Images)
A third dose gives another signal to the immune system to complete its response (Getty Images)

Booster injections help train the body to fully respond to pathogens. A booster shot helps the body create memory cells that are long-lasting and capable of fighting pathogens for periods of time. It basically gives another signal to the immune system to complete its response. They connect the immune system to respond to that pathogenExplained Costi Sifri, Director of Hospital Epidemiology at the University of Virginia Health.

Infectologists consulted by Infobae agree that the use of a third dose is a valid health strategy in certain circumstances and in immunosuppressed patients, but they do not advise it today to the general population and they recommend reaching as many of the population as possible with two doses in advance.

Keep reading:

A study confirmed that the vaccines used in Argentina generated a strong cellular immune response

COVID-19: a study showed that complete vaccination reduced mortality by 96.6% in the city of Buenos Aires

What says the first preliminary study of a combination of vaccines against COVID-19 conducted in Argentina

COVID vaccination in children: 10 securities under the eye of an expert

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