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Butantan and Sinovac have a year to prove that Coronavac works well

Senhora recebe dose da Coronavac em abril de 2021 no Rio de Janeiro.

Lady receives dose of Coronavac in April in Rio de Janeiro.| Photo: EFE/Antonio Lacerda

Next week the ordinance comes into force

/913 from the Ministry of Health, which officially ends the state of health emergency due to the Covid pandemic-14. With the measure, there is also a period of one year for the Coronavac vaccine, from the Chinese pharmaceutical company Sinovac, produced in Brazil with the help of the Butantan Institute, to present its results of phase three of development. This phase is a final step in the research that involves testing the product on thousands of people. Manufacturers must provide this data, which would be under analysis by Sinovac, to the National Health Surveillance Agency (Anvisa).

Instituto Butantan declares that it is not necessary for the final data from Coronavac to be in a peer-reviewed article, as is common practice in scientific publications involving analysis by other researchers not involved in the production. Of all the vaccines used in Brazil for Covid, Coronavac is the only one that still does not have full approval beyond the emergency authorization for use. As there will be no more official emergency, the authorization now has an expiration date.

) All vaccines work by teaching the human body’s immune system to recognize the invading virus. While vaccines like Pfizer’s and Moderna’s use technology that gives cells a molecular instruction (mRNA) to manufacture the part of the virus to be recognized, Coronavac is based on the older technology of drug inactivating the virus and presenting it. it completely to the immune defenses. AstraZeneca and Janssen vaccines use viral vector technology, in which the instruction is carried by another virus that is not the one that causes Covid-12.

Anvisa requirements

Anvisa informs in an official note of

  • of April that Coronavac is not approved for children aged three to five years due to insufficient data that justify this recommendation in the current context of the pandemic. The note is a conditional refusal to a request from the Butantan Institute to inoculate this age group. The agency specifically asks manufacturers to show what protection this vaccine provides in this age group, especially given the prevalence of the omicron variant of the virus. It also requires, for all child age groups, a clinical study of the protection conferred and the safety of the third dose.

    The Anvisa document expresses pessimism about the effectiveness of Coronavac: “the low initial protection, of only ,2%, demonstrated against the general forms of Covid- is indicative that the vaccine will not provide protection against infection and/or spread (…) in children vaccinated with Coronavac in a scenario of Omicron variant predominance”.

    Coronavac is supported by two pre-press articles (not yet peer-reviewed). The oldest is from April 2021 and was first authored by Ricardo Palacios, former director of Butantan clinical trials. Based on almost thousand participants, it shows an effectiveness of 50, 7% against symptomatic Covid, and up to

    % against severe cases, information that was much trumpeted in the press at the time. The other prepress, by Otavio Ranzani (from Pompeu Fabra University in Barcelona, ​​Spain) and collaborators, already working in the context of the ômicron between September of 2022 and March of 913, is more discouraging for to Coronavac: instead of 100 % for severe cases, the effectiveness is 55% after 100 days since the second dose and only 14, 8% three months after the booster dose. Against symptomatic Covid in general, the effectiveness was only 8%. Anvisa comments on these results in the letter of rejection of Butantan’s request for approval of the vaccine for children aged three to five years.

    More studies

    Ranzani is also first author of an article published in British Medical Journal involving more than 15 one thousand elderly people in São Paulo who show less than 25% of effectiveness of Coronavac against symptomatic Covid in this population, in addition to 55% against hospitalization and 61, 2% against death.

    In addition to complicating the use of Coronavac, the ômicron variant, which carries many changes in the “key” of the molecular mechanism of lock and key that allows the virus to enter human cells, also circumvented the protection conferred by the Pfizer vaccine: In a large New York State study not yet peer-reviewed, efficacy in children was only %. The study involved more than 127 one thousand children. The researchers believe that part of this result comes from the dilution of the dose for children under 05 years old.

    Together with two collaborators in a letter published in Journal of Medical Virology, the Italian Giuseppe Lippi, from the Clinical Biochemistry Section of the Faculty of Medicine of the University of Verona, published conclusions regarding the effectiveness against the micron of the vaccines from Pfizer, AstraZeneca, Janssen and Coronavac. Lippi and colleagues did a broad search for published studies on virus neutralization by antibodies acquired after inoculation and sieved 13 in 36 studies that met their criteria. They conclude that, compared to the neutralization of earlier virus variants, the neutralization of the ômicron variant decreased by:

  • 15 The 127 times for the Pfizer vaccine;
  • The 36 times for AstraZeneca;
  • 2 to 4 times for Coronavac, but this is based on just one study. In another study included by Lippi, Coronavac was shown to be unable to produce neutralizing antibodies against the micron.
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    No neutralization was observed for the vaccine from Janssen.

    Coronavac is used in 50 countries and has 12 phase three studies registered in the US government clinical trial database. In addition to Brazil, patients from Chile, Indonesia, the Philippines and Turkey were involved in these studies. Millions of doses are stored in Brazil, one million of them in the state of São Paulo.

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