The keys to understanding the possible vaccine combinations

While the Ministry of Health summoned researchers to carry out studies to analyze combined schemes of vaccines against covid-19 in the country, the United Kingdom, Spain and Germany have already released preliminary works that showed good results in the immune response and safety to the exchange the immunizers in the second doses. For this step in injections, it can be helpful to consider several key issues.

What is the vaccine combination?

The combination of vaccines is to use in the vaccination schedule different inoculants for the first and second doses, which are called heterologous schedules.

“Sputnik V is itself a heterologous scheme because it uses a different viral vector for each dose: it uses adenovirus 26 (a virus that causes a common flu in people) for the first dose and adenovirus 5 for the second”, indicated to the official news agency Télam Humberto Debat, virologist and member of the Argentine Interinstitutional Project of SARS-CoV-2 genomics (PAIS).

Can all vaccines be combined?

The vaccines developed against the coronavirus use different platforms (technology); some are inactivated viruses (such as Sinopharm), others are from non-replicative viral vectors (such as Sputnik V or Astrazeneca), others from messenger RNA (such as Pfizer and Moderna).

In the studies that are being carried out, different platforms are being combined.

“One of the combination hypotheses is that if different platforms are used in the same scheme, it can induce different immune responses that could be complementary,” Debat described.

What are the studies that have been done so far?

Preliminary results were good for safety and immunogenicity (measurement of immune response). One of the heterologous scheme studies was carried out in Spain (CombiVacS) and was published in The Lancet. In this work, a second dose of Pfizer was administered to 448 people who had received the first dose of Astrazeneca.

After analyzing immunogenicity by measuring neutralizing antibodies and monitoring adverse effects, the researchers concluded that the combination “induced a robust immune response, with a manageable reactogenicity (adverse effects) profile.”

A study called Com-COV is underway in the UK, the first of which was published in May in The Lancet. In this article, the initial reactogenicity results (short time from the application of the vaccines) of two schedules were reported: one with Astrazeneca as the first dose and with Pfizer as the second and another inverted schedule.

The researchers found “greater reactogenicity after the booster dose reported by participants in the heterologous vaccination programs compared to the homologous vaccine programs,” although in all cases the symptoms were short-lived, finding nothing of concern in laboratory tests or severity responses.

Last Monday, the authors of this study reported that the combination of these vaccines induced a robust immune response, and the antibody measurement was higher in the group that had received the heterologous scheme than in those who had received the scheme with the same vaccine. The work is not yet published with peer review.

A third study, also not yet published in a peer-reviewed journal, conducted by researchers at the University of Saar, in Homburg, Germany, found that regimens combining the Astrazeneca and Pfizer vaccine were better at eliciting a response. immune system than two injections of it.

Currently there are many other studies in progress that combine the Sputnik V, Novavax or Moderna vaccines with Astrazeneca, and one in the Philippines to test CoronaVac (from the Chinese laboratory Sinovac) with the six that are being used in that country.

What is the use of combining vaccines?

The high effectiveness of the first doses of all approved vaccines, both in the protection of symptomatic covid-19 and in the development of severe cases and death, has been proven in several countries. The second doses improve the response of the immune system and extend it over time.

However, in the face of the emergence of new, more contagious and possibly more aggressive variants (although this is still under study), the application of the second dose to reinforce protection has become more necessary and not all countries have the complete treatment schemes available. the same vaccine for the entire population.

In this context, the possibility of combining vaccines is a tool in the face of global shortages and would allow countries to combine according to availability. But the possibility of having heterologous schemes could also be useful in certain situations.

The Minister of Health, Carla Vizzotti, already gave as an example the case of a person who had adverse effects with a vaccine, “then to complete the scheme another can be offered”; or “either the case of the countries that do not have a registry of the vaccine that they applied and the person loses their license”; or “also in the case that a person is going to complete their schedule and in the vaccination they do not have the same vaccine that they were given before.” Finally, some combinations are aimed at improving efficiency.

In the city

The Ministry of Health of the City of Buenos Aires will initiate a study in which people over 21 years of age who have received the first component of Sputnik V for 30 days or more will be able to enroll voluntarily, to whom the second component of Sputnik, Sinopharm or Astrazeneca.

How the Argentina study will be conducted

On Thursday, the Ministry of Health launched a call for research groups to analyze the efficacy, immunogenicity and safety of the use of different doses of coronavirus vaccines in the same scheme and their response to variants of the SARS-CoV-2 virus. .

The multicenter study will be carried out based on the combination of the vaccines available in Argentina with a collaborative design that allows the participation of researchers from all interested jurisdictions.

In addition, it will be proposed to evaluate the results of the schemes applied to have information and analyze in the future if it is necessary to apply reinforcements and the extension of protection.

Researchers from the National Council for Scientific and Technical Research (Conicet) and from different universities approached the call for proposals.

A millionaire payment if the vaccine proves fatal

Record. Argentina exceeded 50% of those vaccinated over 18 years of age and on Friday a new record was reached with more than 471 thousand applications in one day.

Signed by President Alberto Fernández, yesterday the decree of necessity and urgency (DNU) was published in the Official Gazette so that Argentina can buy American vaccines from Pfizer, Moderna and Johnson & Johnson. The DNU includes a millionaire payment if the vaccine causes the death of the inoculated.

DNU 431 modifies article 4 of Law 27,573, inasmuch as it eliminates the cause of “negligence” as an attribute of the supplier’s responsibility and replaces the terms “fraudulent maneuvers and malicious conduct” with “fraudulent conduct”, a concept that is accepted in the terminology of the Civil and Commercial Code.

Article 1 replaces Article 3 of Law 27,573 and establishes that “the waiver to oppose the defense of sovereign immunity will not imply any waiver with respect to the immunity of Argentina with any property, reserve or account of the Central Bank.” Nor does it cover “any good located within or outside the Argentine territory that provides an essential public service.”

Goods “in the form of cash, deposits or any other means of payment in the country” are also excluded. Neither does it contemplate taxes owed and the rights of the country to collect them, nor goods under the control of a military authority; any good that is part of the cultural heritage of Argentina, and any good that makes up the Sustainability Guarantee Fund “.

Article 2 replaces Article 4 and empowers the Ministry of Health to “include in contracts for the acquisition of vaccines clauses that establish conditions of patrimonial indemnity with respect to compensation.”

Article 3 incorporates as article 8 bis the creation of the Covid-19 Reparation Fund, which will be aimed at “paying compensation to human persons who have suffered damage to physical health, as a direct consequence of the application of the intended vaccine. against the coronavirus “.

“The compensation payable by the Fund for the death or total and permanent physical disability of the injured party will be equal to 240 times the minimum retirement pension,” which currently amounts to approximately 5 million pesos.

Article 10 of the DNU incorporates as article 8 that the fund must be constituted with a sum equal to 1.25 percent of the FCA (Free Carrier) value per dose of the vaccines supplied.

“This decree has as one of its objectives access to (vaccines) by the population, especially for boys, girls and adolescents,” Alberto explained in the text published yesterday in the Official Gazette.

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