What is the effectiveness of the new bivalent vaccines against COVID-19

Si se analizan los efectos largo plazo, el analisis de los specialistos sugête que las diferencias aportadas por las nuevas vacunas podridán ser insignificantes (Getty)
Si se analizan los efectos largo plazo, el analisis de los specialistos sugête que las diferencias aportadas por las nuevas vacunas podridán ser insignificantes (Getty)

Con la noticia aún fresca de la emergency authorization por parte de las agencias regulatorias de los EEUU y Europe, se conocieron los results de un preliminary analysis, que suguete que The updated reinforcements offer almost the same level of protection as an additional dose of the older vaccines, particularly when it comes to avoiding serious forms of COVID-19.

El estudio se publicó en el server de preimpresión de medRxiv el 26 de agosto y aún no fue revisado por pares. Sin embargo.

The hope was that the updated vaccines, based on the Ómicron variant of SARS-CoV-2, would offer substantially greater protection than the older vaccines based on the strain of the virus that emerged in 2019 in Wuhan.

But tras conocerse los ultimos studies, John Moore, científico de vacunas de Weill Cornell Medicine en la ciudad de Nueva York, recognized that “Esto no es una especie de súper escudo contra la infección en comparison con lo que podría haber obtenido hace dos semanas o hace un mes”.

For the expert, who did not participate in the study, “the regulators of the EU and the United Kingdom should have taken into account the potential effectiveness of the updated vaccines before they were authorized”.

FILE PHOTO: Labeled test tube
FILE PHOTO: Test tube labeled “COVID-19 Omicron variant test positive” is seen in this illustration picture taken January 15, 2022. REUTERS/Dado Ruvic/Illustration/File Photo

On August 15, the United Kingdom became the first country to authorize the emergency use of one of the new “bivalent” vaccines, developed against the Ómicron BA.1 lineage as well as against the original sequence of SARS-CoV-2 identificada en Wuhan, China. Next, the Administration of Alimentos and Medicines (FDA) of the USA gave the green light to similar bivalent vaccines.

Ocurre que los ensayos de eficacy a grand escala habien shown that the first generation of vaccines against the COVID-19 reducía el risego de enfermedad en más del 90%. But such studies, which involved the aleatory assignment of tens of thousands of people to receive a vaccine or a placebo and then follow these people to see who is infected, are not practical, possible or ethical in 2022.

Instead, the updated COVID-19 vaccines were tested in smaller groups. Para medir su eficacia, los desarrolladores normally midieron las respuestas munitarias de los participants, en particular los levels de cuerpos de cuerpos “neutralizantes” que blockean la infección, y los compararon con los de las people que received otra dosis de la vacuna original.

En ese sentido, la majority de estos ensayos encontaron que las vacunas actualizadas, basadas no sólo en Ómicron, sino también en variants más antiguas, incluida Beta, funcionaron un poco mejor in terms de esta medida que las vacunas originales. “Este es un refuerzo clearly superior”, había announced the president of the Moderna pharmaceutical firm Stephen Hoge to los inversionistas last June 8, al promocionar tales resultados de la vacuna bivalente basada en BA.1 de la compañía.

Muchos científicos questionan la decisión de buscar refuerzos contra las variants cuando el beneficio es tan pequeño
Muchos científicos questionan la decisión de buscar refuerzos contra las variants cuando el beneficio es tan pequeño

To make sense of the results of Moderna, a team led by Deborah Cromer, a mathematical modeler at the University of New South Wales (UNSW) in Sydney, Australia, collected all the updated results of the vaccine trials that the researchers could find. encontrar, como así como studies que analizan la eficacia de la cuarta dosis de la vacuna original.

Both types of vaccines raised the levels of antibodies, but the updated versions made them levels that were, on average, 1.5 times higher than the older vaccines based on the original sequence of SARS-CoV-2. “No estamos hablando de un cambio radical”, recognized Cromer.

The truth is that the studies suggest that the highest levels of neutralizing antibodies provided by the new formulations are equivalent to a better protection against COVID-19, but it is not clear from the updated vaccine trials how much more effective they could be.

To determine this, the Cromer team applied a model that she, UNSW immunologist Miles Davenport and her colleagues developed by relating the effectiveness of the original COVID-19 vaccines to antibody levels. That’s how it was The researchers found that the majority of the benefits provided by the updated vaccines were transmitted through an additional dose of any of the available vaccines.

They exemplified: In a population where half of the people are protected against a symptomatic infection by SARS-CoV-2 through a vaccination or previous infection, an updated vaccination booster increased the protection to 90%, compared to The 86% protection provided by an additional dose of the original vaccine. Sin embargo, para la protección contra enfermedades graves, la diferencia en la protección fue inferior al 1%.

The findings show relief that second-generation vaccines may not meet the goal they were created to stop the circulation of new, more transmissible variants (AFP).
The findings show relief that second-generation vaccines may not meet the goal they were created to stop the circulation of new, more transmissible variants (AFP).

En tanto, a nivel de población, los inquisitors creen que las vacunas actualizadas podriden tener sentido. El equipo de Cromer estimated that, por cada mil personas, a booster campaign based on updated vaccines would result in eight fewer hospitalizations, on average, than one based on old vaccines. “Si eso se traduce en camas de hospital salvadas y casos graves evitados, ese podría ser un nivel suficiente para justifyar la recommendation de un refuerzo con una variante modificada”, he considered.

Si se analizan los efectos a largo plazo, el análisis de Cromer suggests que las diferencias podería ser insignificantes. Even the updated vaccines based on the Beta and Delta variants should be protected against the BA.4 and BA.5 infections almost as much as the vaccines based on the main variants. In a similar way, the bivalent vaccines that include the original vaccine are not more effective than the vaccines based solely on a new variant.

Para Dean Follmann, statistician of the National Institute of Allergies and Infectious Diseases of the USA in Bethesda, Maryland, including the marginal benefits of a vaccine based on BA.4 and BA.5 could be sufficient to justify its implementation. “Probably sea algo mejor.” Mucho mejor, probabilidad no”, he recognized, al tiempo que sugirió que el mensaje principal del análisis debbie ser que cualquier refuerzo de COVID-19 es bueno.

Otros científicos questionan la decisión de buscar refuerzos contra las variants cuando el beneficio es tan pequeño. A Moore, por ejemplo, le preocupa que la gente thinke que las vacunas actualizadas son mucho más efectivas que las vacunas existentes cuando no lo son y, por lo tanto, podriane exponerse a majores riesgos de infección.

In the same line, Paul Offit, vaccine scientist at the Infantil Hospital of Philadelphia in Pennsylvania, asked “si esta vacuna no es más efectiva que las vacunas actuales, ¿por qué distributarla?”. The expert, who was one of the two members of the advisory committee of the FDA who voted against updating the vaccines against the COVID-19, considered that the update of the formulations “will have very little impact on the incidence of diseases” graves”.

SEGUIR LEYENDO

Leave a Reply

Your email address will not be published.