Pfizer’s Covid Vaccine Prevents 90% of Infections in Study
La vacuna Covid de Pfizer previene el 90% de las infecciones en el estudio
By , , and 9 de noviembre de 2020
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Preliminary results could pave way for vaccine by year-end
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Pfizer, BioNTech expect to get two-month safety data next week
The Covid-19 vaccine being developed by Pfizer Inc. and BioNTech SE prevented more than 90% of infections in a study of tens of thousands of volunteers, the most encouraging scientific advance so far in the battle against the coronavirus.
Eight months into the worst pandemic in a century, the preliminary results pave the way for the companies to seek an emergency-use authorization from regulators if further research shows the shot is also safe.
Pfizer shares extended gains in premarket trading, rising about 15%, with BioNTech American depositary receipts up about 22%. The news added more than $500 billion to the value of the MSCI All Country World Index.
La vacuna Covid-19 que está siendo desarrollada por Pfizer Inc. y BioNTech SE previno más del 90% de las infecciones en un estudio de decenas de miles de voluntarios, el avance científico más alentador hasta ahora en la batalla contra el coronavirus.
Ocho meses después de la peor pandemia en un siglo, los resultados preliminares preparan el camino para que las compañías busquen una autorización de uso de emergencia de los reguladores si las investigaciones posteriores muestran que la vacuna también es segura.
Las acciones de Pfizer han extendido las ganancias en el comercio pre-mercado, subiendo alrededor del 15%, con los recibos de depósito de BioNTech American subiendo alrededor del 22%. La noticia añadió más de 500.000 millones de dólares al valor del MSCI All Country World Index.The findings are based on an interim analysis conducted after 94 participants, split between those who got a placebo and those who were vaccinated, contracted Covid-19. The trial will continue until 164 cases have occurred. If the data hold up and a key safety readout Pfizer expects in about a week also looks good, it could mean that the world has a vital new tool to control a pandemic that has killed more than 1.2 million people worldwide.
“This is about the best the news could possibly be for the world and for the United States and for public health,” said William Gruber, Pfizer senior vice president for vaccine clinical research and development. It was better than even the best result he had hoped for, he said.
Ugur Sahin
Courtesy: BioNTech
With effectiveness for the first vaccines previously expected to be in the range of 60% to 70%, “more than 90% is extraordinary,” BioNTech Chief Executive Officer Ugur Sahin said.
‘Victory of Science’
“It shows that Covid-19 can be controlled,” Sahin said in an interview. “At the end of the day, it’s really a victory of science.”
The data do have limits. For now, few details on the vaccine’s efficacy are available. It isn’t known how well the shot works in key subgroups, such as the elderly. Those analyses haven’t been conducted. And it isn’t known whether the vaccine prevents severe disease, as none of the participants who got Covid-19 in this round of analysis had severe cases, Gruber said.
However, the strong reading from the first large-scale trial to post efficacy results bodes well for other experimental vaccines, in particular one being developed by Moderna Inc. that uses similar technology. Its big trial could generate efficacy and safety results in weeks. If that study succeeds as well, there could be two vaccines available in the U.S. by around year-end.
Pfizer expects to get two months of safety follow-up data, a key metric required by U.S. regulators before an emergency authorization is granted, in the third week in November. If those findings raise no problems, Pfizer could apply for an authorization in the U.S. this month. A rolling review began in Europe last month, and Sahin said regulators there are working with BioNTech to “further accelerate the process.”
So far, the trial’s data monitoring committee has identified no serious safety concerns, Pfizer and BioNTech said.
Demuestra que el Covid-19 puede ser controlado", dijo Sahin en una entrevista. "Al final del día, es realmente una victoria de la ciencia."
Los datos tienen límites. Por ahora, hay pocos detalles sobre la eficacia de la vacuna. No se sabe qué tan bien funciona la vacuna en subgrupos clave, como los ancianos. Esos análisis no se han realizado. Y no se sabe si la vacuna previene la enfermedad grave, ya que ninguno de los participantes que recibieron Covid-19 en esta ronda de análisis tuvo casos graves, dijo Gruber.
Sin embargo, la fuerte lectura del primer ensayo a gran escala para publicar los resultados de eficacia es un buen augurio para otras vacunas experimentales, en particular una que está siendo desarrollada por Moderna Inc. que utiliza una tecnología similar. Su gran ensayo podría generar resultados de eficacia y seguridad en semanas. Si ese estudio tiene éxito también, podría haber dos vacunas disponibles en los EE.UU. alrededor de fin de año.
Pfizer espera obtener dos meses de datos de seguimiento de la seguridad, una medida clave requerida por los reguladores de EE.UU. antes de que se conceda una autorización de emergencia, en la tercera semana de noviembre. Si esos hallazgos no plantean problemas, Pfizer podría solicitar una autorización en los EE.UU. este mes. Una revisión continua comenzó en Europa el mes pasado, y Sahin dijo que los reguladores de allí están trabajando con BioNTech para "acelerar más el proceso".
Hasta ahora, el comité de monitoreo de datos del ensayo no ha identificado ninguna preocupación seria de seguridad, dijeron Pfizer y BioNTech.Leading the Race
The positive preliminary data mean the U.S. pharma giant and its German partner are on track to be first with a vaccine, after signing advance deals with governments worldwide for hundreds of thousands of doses. The companies have said they should be able to produce 1.3 billion doses -- enough to vaccinate 650 million people -- by the end of 2021. Only 50 million doses are expected to be available in 2020.
The shot relies on messenger RNA technology never before used in an approved medicine. Using mRNA, which essentially teaches the body’s cells to become vaccine factories, allowed it to be developed much faster than a traditional vaccine.
Pfizer had originally planned to conduct a first analysis of trial data after just 32 virus cases had occurred in the trial, which has enrolled 43,538 volunteers in multiple countries. Analyzing the data that early proved controversial among medical experts. Other companies working on vaccines planned to wait longer before scrutinizing trial information.
After discussion with U.S. regulators, Pfizer and BioNTech said they recently elected to drop the 32-case analysis and conduct the first analysis at a minimum of 62 cases, one of several changes made in the trial-analysis plan.
While Pfizer conducted those negotiations, it paused testing of participant samples for the virus, said Gruber. By the time Pfizer had made the changes in the trial plan and restarted virus testing a few days ago, some 94 cases had occurred, far more than the trial needed to meet the new threshold.
Pfizer raced to verify the data, which were still blinded to almost everyone at the company beside a few statisticians. Early on Sunday afternoon, an independent data monitoring committee that included a noted statistician and four infectious-disease experts met in a closed video session to review the results for the first time. Afterward, the panel brought Gruber, Sahin and other company representatives onto the call and told them the vaccine had easily achieved its efficacy goal.
“Everyone is pretty ecstatic,” said Gruber. He said that further details on the case breakdown weren’t aavailable.Uncertain Duration
The vaccine is being tested in a two-dose regimen. The trial started in July, and since most participants only received their second dose much more recently, nobody knows how long any protection will last.
Pfizer has found itself drawn into a contentious political debate about how quickly regulators in the U.S. should allow a vaccine to be given to Americans. President Donald Trump pushed to have a shot approved before Election Day, but regulators put in place rigorous standards that largely pushed that goal out of reach.
On Oct. 16, Pfizer Chief Executive Officer Albert Bourla said the companies could seek an emergency use authorization from U.S. regulators by late November if the trial results were to show the shot is safe and effective. Writing in an open letter, Bourla quelled fears that Pfizer might be racing the clock to bring out a vaccine before the presidential election.
Moderna is considered the next closest vaccine frontrunner. It has said it could get safety and efficacy data from its late-stage trial this month. Johnson & Johnson, which has a one-shot vaccine using a different technology, could get efficacy data from a final stage trial by the end of this year. AstraZeneca Plc is also working on a vaccine using different technology, with results from studies in the U.K. and Brazil expected by year-end.
— With assistance by Celeste Perri
La vacuna se está probando en un régimen de dos dosis. El ensayo comenzó en julio, y como la mayoría de los participantes sólo recibieron su segunda dosis mucho más recientemente, nadie sabe cuánto tiempo durará la protección.
Pfizer se ha visto envuelta en un polémico debate político sobre la rapidez con la que los reguladores de los EE.UU. deben permitir que se administre la vacuna a los estadounidenses. El presidente Donald Trump presionó para que se aprobara una vacuna antes del día de las elecciones, pero los reguladores establecieron normas rigurosas que en gran medida hicieron que ese objetivo estuviera fuera de alcance.
El 16 de octubre, el director ejecutivo de Pfizer, Albert Bourla, dijo que las compañías podrían solicitar una autorización de uso de emergencia a los reguladores estadounidenses para finales de noviembre si los resultados de las pruebas demuestran que la vacuna es segura y eficaz. En una carta abierta, Bourla acalló los temores de que Pfizer pudiera estar corriendo el reloj para sacar una vacuna antes de las elecciones presidenciales.
Moderna está considerada como la siguiente vacuna más cercana a la delantera. Ha dicho que podría obtener datos de seguridad y eficacia de su ensayo de última etapa este mes. Johnson & Johnson, que tiene una vacuna de una sola dosis que utiliza una tecnología diferente, podría obtener datos de eficacia de una etapa final de prueba a finales de este año. AstraZeneca Plc también está trabajando en una vacuna que utiliza una tecnología diferente, con resultados de estudios en el Reino Unido y Brasil que se esperan para finales de año.
https://www.bloomberg.com/news/articles/2020-11-09/pfizer-s-covid-vaccine-prevents-90-of-infections-in-large-study?fbclid=IwAR0RCTvfvr_X-7KyufDOp4MriG3ULcCjXsKwr8Sw7y0Iy0NG5efFObnO8EM
¿Cómo funciona esta vacuna? 
. El sistema inmune empieza a fabricar soldados como las células T y los anticuerpos. Estos soldados van a tope de entrenados para liquidar al coronavirus. 
Pfizer no participó en la Operación Warp Speed de la Administración Trump y no aceptó subsidios gubernamentales. Tiene éxito porque fue construido para la velocidad y realiza pruebas en muchos países, no solo en los EE. UU. (Extracto de NYT Sept)
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