Les USA lancent un plan massif de test des vaccins expérimentaux contre le coronavirus - sources

Exclusive: U.S. plans massive coronavirus vaccine testing effort to meet year-end deadline | Article [AMP] | Reuters
▻https://www.reuters.com/article/health-coronavirus-usa-vaccine-exclusive-idINKBN22Z07F

Trials will need to assess if the vaccines cause disease enhancement - a potentially dangerous side effect in which the vaccine makes the disease worse in some individuals instead of preventing it. Disease enhancement has been seen in animal studies of vaccines developed to fight a close cousin of the virus that causes COVID-19.

“If there is enhancement, that’s a big stop sign for everything,” said Dr. Anthony Fauci, director of the National Institutes of Allergy and Infectious Diseases at NIH.

“If all the cards fall into the right place and all the stars are aligned, you definitely could get a vaccine by December or January,” Fauci said.

COVID-19 Vaccine Won’t Be a Slam Dunk
▻https://www.medscape.com/viewarticle/930986

Une préoccupation de sécurité clé à surveiller dans les mois à venir est de savoir si un vaccin candidat est capable de contourner le problème du “#antibody-dependent_enhancement” (#facilitation_de_l'infection_par_des_anticorps ▻https://fr.wikipedia.org/wiki/Facilitation_de_l%27infection_par_des_anticorps), par lequel une infection antérieure par un coronavirus non SRAS, comme ceux qui causent le rhume, pourrait entraîner la création d’anticorps anti coronavirus peu neutralisants en réponse à la vaccination. Il est à craindre que ces anticorps non neutralisants puissent faciliter l’entrée du virus dans les monocytes et autres cellules dépourvues du récepteur ACE2, sa porte d’entrée habituelle. En réaction, cela pourrait déclencher une réplication virale étendue, une réponse hyperinflammatoire et une propagation virale vers des sites au-delà des poumons, comme le cœur ou les reins.

Illustré ci-dessous,
▻https://www.nature.com/scitable/content/model-of-antibody-dependent-enhancement-of-dengue-22403433

https://www.nature.com/scitable/content/ne0000/ne0000/ne0000/ne0000/22403433/F3_dengue_1_2.jpg

Targets of T cell responses to SARS-CoV-2 coronavirus in humans with COVID-19 disease and unexposed…
▻https://seenthis.net/messages/853439#message853693

Les résultats de cette étude sont rassurants quant au phénomène de la #facilitation_de_l'infection_par_des_anticorps

The other good news is that this team looked for the signs of an #antibody-dependent-enhancement response, which would be bad news, and did not find evidence of it in the recovering patients (I didn’t go into these details, but wanted to mention that finding, which is quite reassuring).

SARS-CoV2 vaccines : Slow is fast | Science Advances
▻https://seenthis.net/messages/855077

Many advocate “fast-tracking” these trials, and some wish to rely soley on evidence of induction of neutralizing responses. However, this could be catastrophic. In 1966, a large trial of a vaccine for Respiratory Syncytial Virus (RSV) found that the immunized cohort actually faired significantly worse upon infection. There is some reason to worry that the same may occur with some SARS-CoV2 vaccines.

Vaccins Covid-19, rêve ou réalité ?
▻https://seenthis.net/messages/856424

Anthony Fauci on Covid-19 reopenings, vaccines, and ’warp speed’
▻https://www.statnews.com/2020/06/01/anthony-fauci-on-covid-19-reopenings-vaccines-and-moving-at-warp-speed

There’s a lot of interest in developing vaccine as quickly as possible, but there’s also a lot of concern about the speed at which this is being undertaken. Should there be major adverse events associated with use of these vaccines, it could really damage trust in vaccination in general. Is that something you are worrying about?

Yes, I am.