Traits of coronavirus vaccines debated between scientists and governments

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Facing a slow deployment of the vaccine, increasing COVID-19[feminine algunes morts i l’amenaça que una variant perillosa del virus s’estengui a tot el país, alguns científics demanen que es redueixin o es retardin les dosis de vacuna en un esforç urgent per aconseguir tirs ràpidament a tanta gent com sigui possible. Però altres científics i reguladors nord-americans retrocedeixen, preocupats perquè aquest canvi de pla pugui tenir conseqüències desastroses.

El creixent desacord enfronta els experts amb els experts, just quan comencen a rebre els primers nord-americans a rebre vacunes COVID-19 els seus segons tirs.

Ningú no sap amb seguretat l’eficàcia d’una sola dosi o durant quant de temps, atès que es van establir assajos clínics per provar un programa de dues dosis. I el que és pitjor, hi ha temors que oferir a la gent només una protecció parcial podria augmentar les possibilitats de la protecció virus que evoluciona per resistir els efectes de les vacunes.

Tot i això, alguns científics diuen que les circumstàncies requereixen mesures extraordinàries. “Quan es tracta de COVID-19, se’ns fa un cop de puny a la boca una i altra vegada. És hora de canviar el pla “, van escriure Ashish Jha de la Brown University i Bob Wachter de la University of California, San Francisco, a un editorial del Washington Post diumenge, demanant que es doni la vacuna a tanta gent com sigui possible i retardant les segones preses fins que es facin més dosis.

El cap de l’Administració d’aliments i medicaments, Stephen Hahn, i el director del centre de vacunes de l’agència, Peter Marks, van rebutjar qualsevol canvi al pla actual en un declaració va publicar dilluns al vespre, dient: “En aquest moment, suggerir canvis en la dosificació o els calendaris autoritzats per la FDA d’aquestes vacunes és prematur i no està arrelat de manera sòlida en les proves disponibles”.

Dues vacunes, un fabricat per Pfizer i l’altre per Moderna, van ser autoritzats el mes passat per a ús d’emergència als EUA. Els assaigs clínics a gran escala van trobar que dues dosis van ser altament protectores durant mesos contra el COVID-19 quan se’ls va administrar a tres o quatre setmanes de diferència. Els signes de reducció del diagnòstic de COVID-19 entre els participants de l’estudi entre les dues dosis no justifiquen canviar aquest calendari, segons van dir Hahn and Marks de la FDA. La Societat de Malalties Infeccioses d’Amèrica va donar suport dimarts a la declaració de la FDA, que va trucar als canvis d’horari “prematur i potencialment nociu“.

1) Si volem generar mutants d’escapament viral difícils al laboratori (per exemple, per al mapatge d’epítops), sotmetem el virus a una pressió baixa d’anticossos i després pujarem lentament. Una mica com després d’una dosi de vacuna. Crec que seria bo donar la segona dosi el més aviat possible.


Twitter: @florian_krammer

“Els assajos clínics van ser dissenyats per donar dues dosis en un horari per una raó. Aquestes són les dades que tenim “, va dir l’expert en vacunes Joel Ernst de la Universitat de Califòrnia, San Francisco. “Crec que l’agència [FDA] it is injecting a dose of operational reality into an interesting and useful scientific debate, which we should also have. “

The Joint Vaccination and Vaccination Committee of the United Kingdom (JCVI) launched the debate last week stretching the time for a second dose of Pfizer vaccine for up to three months, at a time when 1 in 30 Londoners it is believed to be infected with the coronavirus. Most surprisingly, the committee suggested that in the event of an emergency, a second dose of a different vaccine could be used if the first vaccine was not available or if it was not known which vaccine was first administered. The British Society for Immunology reluctantly supported the change of time, citing evidence that a more highly transmissible variant of pandemic coronavirus is behind a surprising rise in cases there.

“What’s happening in the UK reflects an urgent situation there,” said Natalie Dean, a biostatistician at the University of Florida. “I can’t see the United States making these kinds of changes without the transparent process of the FDA and the CDC that led to the first vaccine authorization.”

He B.1.1.7 coronavirus variant, first identified in the UK, complicates calculations of how many people need to be vaccinated, because it is more transmissible. Now seen in more than 30 countries, “in the U.S., we have to assume that this variant is probably over,” Dean said. Although so far it has only been detected in four states, poor genomic surveillance in the US it probably means it is more common than we currently know. Even if it’s widespread, that shouldn’t change the math right now to keep up with current vaccination schedules, Dean said.

In the coming months, from vaccines we will get to know better the antibodies and cells of the immune system that provide protection against infection, he added. “Once we have these protection correlates, we can be more confident of any change in dosage.”

Pfizer and Moderna sent statements from BuzzFeed News on Monday that they supported the second-dose program the FDA had authorized. “While decisions about alternative dosing regimes are up to health authorities, Pfizer believes it is critical to monitor efforts on any alternative schedules implemented and ensure that each recipient has the maximum possible protection, which means vaccination with two doses of the vaccine, ”he said. the Pfizer statement. On Tuesday, a group of experts from the World Health Organization supported Pfizer’s schedule, however, under exceptional circumstances, the second dose could be administered up to six weeks later.

Meanwhile, in the United States, Chief Warp Speed ​​Scientist Moncef Slaoui on Sunday raised the idea of ​​giving them two half doses of the Modern vaccine to stretch supplies. The U.S. National Institutes of Health confirmed that the idea of ​​a half-dose was under study on Tuesday, the The New York Times reported. The fact that Slaoui suggested stretching the offer, however, surprised some experts like his $ 18 billion vaccine the private-public partnership, widely held to rapidly stimulate vaccine development, has been the subject of fire for failing to deliver on its promise to have 20 million shots fired at the end of the year. Only 17 million were delivered and shots were fired to just over 5 million people from Wednesday.

Some public health figures, such as Jha and Wachter, have called on the US to join the UK to extend the time of the second shots. But in its statement Monday night, the FDA suggested that this line of argument exaggerated the safety there was about effectiveness after a shot.

“We have to recognize that every vaccine is different and we don’t know everything,” Ernst said, urging caution. “If we knew everything, we would have had an HIV vaccine 30 years ago.”

For pandemic modeler Marc Lipsitch of Harvard’s TH Chan School of Public Health, the FDA’s position reflects its role as a carrier of new treatments in the U.S.

“The FDA is a regulator. They are not, in their broadest sense, a public health agency; their job is to make sure that the things we inject ourselves into and that we take as pills and supplements and anything that does what is advertised. And in that narrow sense, they are right, “he said in a briefing on Tuesday.

“It’s a really interesting case where science, as regulators see it, and science as public health in the broadest sense, may be a little different,” Lipsitch said.

Peter Aldhous / BuzzFeed News / Via covid.cdc.gov

Doses of vaccines administered by state from 6 January.

The other major concern that many experts have with suggestions for changing the dosing schedule in the United States is that states cannot inject doses already sent. Vaccine launches in general have been slower than advertised, with great variation from state to state.

“This basically makes the ball pass to the 1-yard line,” said virologist Angela Rasmussen of the Georgetown Center for Global Health Science and Security. “Why are we talking about fundamentally modifying the proven dosing regimens when – I have a limited supply of vaccines – when we’re not able to get the supply we have in people’s arms?”

Vaccine projections have been steadily eroded for months in this way, starting with OWS lowering its initial promises of 300 million doses in January, a projection quietly abandoned in August.

Going for a single dose would undermine the last remaining credibility of OpWarpSpeed. If you look at the published data, there are only two doses for the two mRNA vaccines that provide reasonable virus neutralizing antibodies. And there are only two doses that protect https://t.co/r1InUWmTES


Twitter: @PeterHotez

“They’re behind, by their own projections, they’re behind,” said Georges Benjamin, executive director of the American Public Health Association. “The truth of the matter is that we always expected them to be shaken, these are complicated vaccines. But all this tells us that we have to move at a much faster pace to manage shots.

With the billions added in one recently approved expense invoice, and the futures required by the incoming Biden administration, the U.S. must move to administer 2 to 3 million vaccines a day, Benjamin added, to change the pandemic tide. Discussing dosing schedules instead of enrolling retired doctors, dentists, and anyone else who might make an opportunity to take doses parked on the shelves right now is an issue.

“What is the goal? The goal is to stop the pandemic. We must use all the tools we have to stop the pandemic. “

CDC / ACIP / Via cdc.gov

A CDC projection of 10 million doses of vaccines distributed per week within five weeks of launch.

The failure of the US Senate to take over vaccine deployment money in the states until last week, along with storms and holiday seasons, made it difficult to deploy vaccines to medical facilities that already handled numerous COVID-19 cases, said Jim Blumenstock of the Association of ‘States and territorial health agents in BuzzFeed News. “At the end of the day, our fractured healthcare system makes it all that much harder,” he said. “The federal government needs a much stronger role.”

The first stage of vaccine deployment, which takes place in large medical centers and nursing homes, is not where most vaccines are supposed to be done in a few months. On Tuesday afternoon, the Trump administration said it was speeding up a plan to do so start administering vaccines to pharmacies. The eventual plan is to follow how flu vaccines are given, with doctor’s offices, pediatricians and pharmacies offering vaccines. So far this season, some 71 million flu vaccines have been given to American adults in 15 weeks, with more than 8 million shots given in a few weeks, after a low number to begin with. In the fall, CDC’s Amanda Cohn warned that members of her vaccine advisory panel the first six weeks of the implementation of the COVID-19 vaccine would also be marked by a small number of shots before boarding.

“If we look back in three weeks, our conversation about vaccines could be different,” Blumenstock said. Slaoui, of OWS, compared the vaccination campaign against COVID-19 with that of the annual flu, increased by a factor of three to four.

But that sounds optimistic, Walter Orenstein of Emory University, former director of the U.S. National Immunization Program, told BuzzFeed News. He said flu shots, where people know what they are getting, are much easier than COVID-19 vaccines. Influenza vaccines are just one vaccine, without the varied cold chain requirements, the most involved consent requirements, and the reinforcement programming, seen with the COVID-19 vaccines we have now. “We never had a situation like this,” Orenstein said, even compared to the hasty release of a H1N1 flu vaccine in 2009. “Vaccines are not given on their own. The big problem here will be getting people to work together. “

The real threat of the two deficiencies in shooting projections and the discussion about increasing vaccination schedules is that public confidence in vaccines could decline, said Michelle Driedger, a health communications expert at the University of Manitoba. , in Canada. In discussion groups this year, he has found much concern about taking new vaccines. The launch of Canada is done like that of the United States, with the federal government distributing doses to the provinces, which decide how to assign their shots.

“I think the FDA statement was very clear and effective, an excellent public health message,” he said. “I think at the public level you need to understand that the agencies are doing their due diligence.”

Stephanie M. Lee contributed by reporting this story.


January 7, 2021 at 5:26 p.m.

Correction: Angela Rasmussen is at the Georgetown Center for Global Health Science and Security. An earlier version of this message distracted his institution.





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