NEJM

Lifting Universal Masking in Schools — #Covid-19 Incidence among Students and Staff | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMoa2211029

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/2022/nejm_2022.387.issue-21/nejmoa2211029/20221121/images/img_small/nejmoa2211029_f0.jpeg

L’incidence de la #covid-19 à été significativement moindre dans les #écoles qui ont maintenu le port du #masque, alors même que par ailleurs les conditions (nombre d’élèves par classe, aération, etc…) y étaient plus défavorables.

During the 15 weeks after the statewide masking policy was rescinded, the lifting of masking requirements was associated with an additional 44.9 cases per 1000 students and staff (95% confidence interval, 32.6 to 57.1), which corresponded to an estimated 11,901 cases and to 29.4% of the cases in all districts during that time. Districts that chose to sustain masking requirements longer tended to have school buildings that were older and in worse condition and to have more students per classroom than districts that chose to lift masking requirements earlier. In addition, these districts had higher percentages of low-income students, students with disabilities, and students who were English-language learners, as well as higher percentages of Black and Latinx students and staff. Our results support universal masking as an important strategy for reducing Covid-19 incidence in schools and loss of in-person school days. As such, we believe that universal masking may be especially useful for mitigating effects of structural racism in schools, including potential deepening of educational inequities.

The Seeds of Ignorance — Consequences of a Booming Betel-Nut Economy | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMp2203571

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/2022/nejm_2022.387.issue-12/nejmp2203571/20220919/images/img_medium/nejmp2203571_f1.jpeg

#Betel nut’s increasing availability in Asian markets throughout Europe and the Americas1 may ultimately make regulation politically feasible. Such products are always cheap, are fairly easy to find in urban areas, and generally don’t come with a warning label. Once higher-income people are at risk for the harms associated with betel-nut use, it should become easier to foster meaningful awareness of the substance and its adverse effects. For the time being, however, the medical community is stuck on the outside looking in as a largely unregulated industry fuels a global health disaster — a painful reminder of how little progress has been made toward addressing egregious health disparities between privileged and marginalized populations. Perhaps the famed neuroscientist Santiago Ramón y Cajal said it best back in 1899: “Every disease has two causes. The first is pathophysiological; the second, political.”

« #économie » “#politique” #poison #cancer #noix_d’arec

Heat-Induced Brain Vitrification from the Vesuvius Eruption in c.e. 79 | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMc1909867?query=featured_home

Cerebral tissues in human remains are rare archaeological discoveries.1 These tissues are typically saponified, meaning that their triglycerides have been converted to glycerol and fatty acid salts, or soap. In c.e. 79, a volcanic hot ash avalanche rapidly killed the inhabitants of Pompeii and Herculaneum.2 In the 1960s, at the Collegium Augustalium in Herculaneum, a human victim of the avalanche was found lying on a wooden bed, buried by volcanic ash (Fig. S1 in the Supplementary Appendix, available with the full text of this letter at NEJM.org). In this victim’s skull, we discovered apparent brain remains that were vitrified instead of saponified (Figure 1 and Fig. S2).

Vitrification refers to tissue that has been burned at high heat and turned into glass or a glaze. In this victim, these vitrified remains also encrusted the surface of the skull (Fig. S3). Glassy material was undetectable elsewhere in the skeleton or in the adjacent volcanic ash, and it was not found in other locations at the archaeological site. Intracranial mineral residues from victims who died from the eruption at the seashore, presumably at a site of different environmental conditions, showed high iron oxide contents from thermal degradation of heme proteins (indicating the vaporization of body fluids),3 but no putative brain remains were found. A solidified spongy mass entrapped the chest bones in the victim at the Collegium (Fig. S4); this feature in victims of the Vesuvius eruption was unique among those at other archaeological sites, but it can be compared with features of victims of more contemporary events such as the firestorms in Dresden and Hamburg, Germany, during World War II.4

Proteomic investigation of the glassy material inside the skull identified several proteins that are highly expressed in human brain tissues (Table S1). Adipic and margaric fatty acids, components of human hair fat from sebum,5 were detected exclusively in the glassy fragments (Table S2) but not in the adjacent ash or in charcoal from the archaeological site. Fatty acids that are typical of human brain triglycerides were also found in the putative brain material. These substances are common to animals and plants (Table S3); however, no evidence of plants or animals was found at the site from which the victim was recovered.

Features suggesting a maximum temperature of 520°C were detected on charred wood from the Collegium (Fig. S5). This suggests that extreme radiant heat was able to ignite body fat and vaporize soft tissues3; a rapid drop in temperature followed. The detection of glassy material from the victim’s head, of proteins expressed in human brain, and of fatty acids found in human hair indicates the thermally induced preservation of vitrified human brain tissue.

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/2020/nejm_2020.382.issue-4/nejmc1909867/20200117/images/img_medium/nejmc1909867_f1.jpeg

Subcutaneous REGEN-COV Antibody Combination to Prevent #Covid-19 | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMoa2109682

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmoa2109682/20210804/images/img_small/nejmoa2109682_f1.jpeg

… combination of the monoclonal antibodies #casirivimab and #imdevimab

#prévention #anticorps_monoclonaux

#SARS-CoV-2 #Variants and Vaccines | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMsr2105280

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/2021/nejm_2021.385.issue-2/nejmsr2105280/20210705/images/img_small/nejmsr2105280_f1.jpeg

Given the emergence of immunity-evading variants even before vaccines were broadly deployed, it is hard to implicate vaccines or vaccine deployment strategies as the major drivers of immune evasion.

However, prolonged viral replication in the presence of partial immunity in immunocompromised persons or circumstances in which rapid transmission of high titers of virus occurs (e.g., crowded living conditions23) could have contributed to the development of variants that can at least partially escape human immune responses. The use of antibody-based treatments (e.g., monoclonal antibodies or convalescent plasma) in circumstances in which they are of limited or undemonstrated efficacy may further contribute to the evolution of variants of concern that could evade not only these but also other antibody responses.24 Partially effective interventions may therefore encourage viral evolution. In addition, the larger the number of infected persons, the greater the chance that new variants of concern will arise. Hence, effective public health strategies such as social distancing, the use of masks, and the targeted use of effective vaccines that reduce both infection and transmission can help to limit viral evolution. Limiting transmission in the general population is extremely important for slowing the emergence of additional variants of concern.

[…]

So far, there is no good evidence that currently identified variants of concern evade the most important vaccine effect — that of prevention of severe disease. describes key properties of and mutations in five selected variants. The fact that a few key amino acids in the spike protein have changed independently in variants identified in various parts of the world indicates that these are convergent changes and suggests that vaccines that incorporate these selected residues could cover several variants.

#vaccins

#Covid-19 Breakthrough Infections in Vaccinated Health Care Workers | NEJM
►https://www.nejm.org/doi/full/10.1056/NEJMoa2109072

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmoa2109072/20210728/images/img_medium/nejmoa2109072_f1.jpeg

La constatation importante est la corrélation avec le titre d’#anticorps neutralisant ; si c’est confirmé une troisième dose ne serait nécessaire* qu’en-dessous d’une valeur seuil qui resterait à définir.

(* d’autant plus nécessaire que 19% des infectés ont quand même eu des symptômes persistant)

Neutralizing antibody titers in case patients during the peri-infection period were lower than those in matched uninfected controls (case-to-control ratio, 0.361; 95% confidence interval, 0.165 to 0.787). Higher peri-infection neutralizing antibody titers were associated with lower infectivity (higher Ct values). Most breakthrough cases were mild or asymptomatic, although 19% had persistent symptoms (>6 weeks).

#vaccination #immunité

Household Transmission of #SARS-CoV-2 from Children and Adolescents | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMc2031915

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmc2031915/20210720/images/img_xlarge/nejmc2031915_t1.jpeg

(Étude prolongeant la suivante :
Coronavirus : des centaines d’enfants américains infectés en colonie de vacances
►https://seenthis.net/messages/870068)

Les #enfants sont bien contagieux

This retrospective study showed that the efficient transmission of SARS-CoV-2 from school-age children and adolescents to household members led to the hospitalization of adults with secondary cases of Covid-19. In households in which transmission occurred, half the household contacts were infected. The secondary attack rates in this study were probably underestimates because test results were reported by the patients themselves and testing was voluntary. In addition, a third of the index patients returned home from camp after the onset of symptoms, when they were presumably not as infectious as they were before and during the onset of symptoms,5 and two thirds adopted physical distancing because of a known exposure at camp; both of these factors probably reduced the transmission of SARS-CoV-2 in the household. When feasible, children and adolescents with a known exposure to SARS-CoV-2 or a diagnosis of #Covid-19 should remain at home and maintain physical distance from household members.

#contagiosité

Eric Topol sur Twitter : “New NEJM: mRNA vaccine (@BioNTech_Group/Pfizer) holds up very well in lab studies for immune response against B.1. 526 (New York), B.1.429 (California), B.1.1.7(UK)+ E484K #variants 👍” / Twitter
▻https://twitter.com/EricTopol/status/1392585566324068358

BNT162b2-Elicited Neutralization against New SARS-CoV-2 Spike Variants | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMc2106083

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmc2106083/20210511/images/img_medium/nejmc2106083_f1.jpeg

#vaccins

Effectiveness of the BNT162b2 Covid-19 Vaccine against the B.1.1.7 and B.1.351 #Variants | NEJM
▻https://www.nejm.org/doi/10.1056/NEJMc2104974

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmc2104974/20210504/images/img_small/nejmc2104974_t1.jpeg

Effectiveness was estimated to be 87.0% (95% CI, 81.8 to 90.7) against the B.1.1.7 variant and 72.1% (95% CI, 66.4 to 76.8) against the B.1.351 variant [...]

The BNT162b2 vaccine was effective against infection and disease in the population of Qatar, despite the B.1.1.7 and B.1.351 variants being predominant within the country; however, vaccine effectiveness against the B.1.351 variant was approximately 20 percentage points lower than the effectiveness (>90%) reported in the clinical trial1 and in real-world conditions [...] Nevertheless, the reduced protection against infection with the B.1.351 variant did not seem to translate into poor protection against the most severe forms of infection (i.e., those resulting in hospitalization or death), which was robust, at greater than 90%.

#vaccins #sars-cov2

Vaccine Breakthrough Infections with #SARS-CoV-2 Variants | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMoa2105000

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmoa2105000/20210421/images/img_small/nejmoa2105000_f1.jpeg

In accordance with New York State regulations regarding eligibility, 417 employees who had received a second dose of either the BNT162b2 (Pfizer–BioNTech) or mRNA-1273 (Moderna) vaccine at least 2 weeks previously were tested between January 21 and March 17, 2021, and weekly testing continued thereafter.

Deux patientes ont développé une forme légère de la maladie après la deuxième dose de #vaccin, 19 jours pour la première et 36 pour la seconde, le séquençage objectivant des #variants dans les deux cas.

Par ailleurs la #charge_virale de la première patiente était particulièrement élevée.

[...] our observations underscore the importance of the ongoing race between immunization and the natural selection of potential viral escape #mutants.

#covid-19

Efficacy of the ChAdOx1 nCoV-19 Covid-19 Vaccine against the B.1.351 Variant | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMoa2102214

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmoa2102214/20210316/images/img_small/nejmoa2102214_f1.jpeg

L’inefficacité du #vaccin AstraZeneca contre les formes légères et modérées de #COVID-19 en rapport avec le #variant « sud-africain » de #SARS-CoV-2 semble se confirmer.

Il n’y a pas eu de formes graves dans les deux groupes (AZ versus placebo), probablement en rapport avec le fait que les sujets testés étaient peu nombreux et qu’ils avaient moins de 65 ans.

METHODS
We conducted a multicenter, double-blind, randomized, controlled trial to assess the safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) in people not infected with the human immunodeficiency virus (HIV) in South Africa. Participants 18 to less than 65 years of age were assigned in a 1:1 ratio to receive two doses of vaccine containing 5×1010 viral particles or placebo (0.9% sodium chloride solution) 21 to 35 days apart. Serum samples obtained from 25 participants after the second dose were tested by pseudovirus and live-virus neutralization assays against the original D614G virus and the B.1.351 variant. The primary end points were safety and efficacy of the vaccine against laboratory-confirmed symptomatic coronavirus 2019 illness (Covid-19) more than 14 days after the second dose.

RESULTS
Between June 24 and November 9, 2020, we enrolled 2026 HIV-negative adults (median age, 30 years); 1010 and 1011 participants received at least one dose of placebo or vaccine, respectively. Both the pseudovirus and the live-virus neutralization assays showed greater resistance to the B.1.351 variant in serum samples obtained from vaccine recipients than in samples from placebo recipients. In the primary end-point analysis, mild-to-moderate Covid-19 developed in 23 of 717 placebo recipients (3.2%) and in 19 of 750 vaccine recipients (2.5%), for an efficacy of 21.9% (95% confidence interval [CI], −49.9 to 59.8). Among the 42 participants with Covid-19, 39 cases (92.9%) were caused by the B.1.351 variant; vaccine efficacy against this variant, analyzed as a secondary end point, was 10.4% (95% CI, −76.8 to 54.8). The incidence of serious adverse events was balanced between the vaccine and placebo groups.

CONCLUSIONS
A two-dose regimen of the ChAdOx1 nCoV-19 vaccine did not show protection against mild-to-moderate Covid-19 due to the B.1.351 variant.

Antibody Responses in Seropositive Persons after a Single Dose of SARS-CoV-2 mRNA Vaccine | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMc2101667

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmc2101667/20210310/images/img_small/nejmc2101667_f1.jpeg

#Vaccination chez les #SARS-CoV-2 séropositifs.

The antibody titers of vaccinees with preexisting immunity were 10 to 45 times as high as those of vaccinees without preexisting immunity at the same time points after the first vaccine dose (e.g., 25 times as high at 13 to 16 days) and also exceeded the median antibody titers measured in participants without preexisting immunity after the second vaccine dose by more than a factor of 6. Although the antibody titers of the vaccinees without preexisting immunity increased by a factor of 3 after the second vaccine dose, no increase in antibody titers was observed in the Covid-19 survivors who received the second vaccine dose.

#anticorps

Early High-Titer #Plasma Therapy to Prevent Severe #COVID-19 in Older Adults | NEJM
▻https://www.nejm.org/doi/10.1056/NEJMoa2033700

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmoa2033700/20210104/images/img_small/nejmoa2033700_f1.jpeg

Therapies to interrupt the progression of early coronavirus disease 2019 (Covid-19) remain elusive. Among them, convalescent plasma administered to hospitalized patients has been unsuccessful, perhaps because antibodies should be administered earlier in the course of illness.

METHODS
We conducted a randomized, double-blind, placebo-controlled trial of convalescent plasma with high IgG titers against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in older adult patients within 72 hours after the onset of mild Covid-19 symptoms. The primary end point was severe respiratory disease, defined as a respiratory rate of 30 breaths per minute or more, an oxygen saturation of less than 93% while the patient was breathing ambient air, or both. The trial was stopped early at 76% of its projected sample size because cases of Covid-19 in the trial region decreased considerably and steady enrollment of trial patients became virtually impossible.

RESULTS
A total of 160 patients underwent randomization. In the intention-to-treat population, severe respiratory disease developed in 13 of 80 patients (16%) who received convalescent plasma and 25 of 80 patients (31%) who received placebo (relative risk, 0.52; 95% confidence interval [CI], 0.29 to 0.94; P=0.03), with a relative risk reduction of 48%. A modified intention-to-treat analysis that excluded 6 patients who had a primary end-point event before infusion of convalescent plasma or placebo showed a larger effect size (relative risk, 0.40; 95% CI, 0.20 to 0.81). No solicited adverse events were observed.

CONCLUSIONS
Early administration of high-titer convalescent plasma against SARS-CoV-2 to mildly ill infected older adults reduced the progression of Covid-19. (Funded by the Bill and Melinda Gates Foundation and the Fundación INFANT Pandemic Fund; Dirección de Sangre y Medicina Transfusional del Ministerio de Salud number, PAEPCC19, Plataforma de Registro Informatizado de Investigaciones en Salud number, 1421, and ClinicalTrials.gov number, NCT04479163. opens in new tab.)

Antibody Status and Incidence of SARS-CoV-2 Infection in Health Care Workers | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMoa2034545

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmoa2034545/20201223/images/img_small/nejmoa2034545_f1.jpeg

Les anticorps développés après une infection par le #sars-cov2 sont protecteurs.

BACKGROUND
The relationship between the presence of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the risk of subsequent reinfection remains unclear.

METHODS
We investigated the incidence of SARS-CoV-2 infection confirmed by polymerase chain reaction (PCR) in seropositive and seronegative health care workers attending testing of asymptomatic and symptomatic staff at Oxford University Hospitals in the United Kingdom. Baseline antibody status was determined by anti-spike (primary analysis) and anti-nucleocapsid IgG assays, and staff members were followed for up to 31 weeks. We estimated the relative incidence of PCR-positive test results and new symptomatic infection according to antibody status, adjusting for age, participant-reported gender, and changes in incidence over time.

RESULTS
A total of 12,541 health care workers participated and had anti-spike IgG measured; 11,364 were followed up after negative antibody results and 1265 after positive results, including 88 in whom seroconversion occurred during follow-up. A total of 223 anti-spike–seronegative health care workers had a positive PCR test (1.09 per 10,000 days at risk), 100 during screening while they were asymptomatic and 123 while symptomatic, whereas 2 anti-spike–seropositive health care workers had a positive PCR test (0.13 per 10,000 days at risk), and both workers were asymptomatic when tested (adjusted incidence rate ratio, 0.11; 95% confidence interval, 0.03 to 0.44; P=0.002). There were no symptomatic infections in workers with anti-spike antibodies. Rate ratios were similar when the anti-nucleocapsid IgG assay was used alone or in combination with the anti-spike IgG assay to determine baseline status.

CONCLUSIONS
The presence of anti-spike or anti-nucleocapsid IgG antibodies was associated with a substantially reduced risk of SARS-CoV-2 reinfection in the ensuing 6 months. (Funded by the U.K. Government Department of Health and Social Care and others.)

#anticorps #immunité

Traitement du COVID-19 par du plasma de convalescents.

Convalescent #plasma in the management of moderate #covid-19 in adults in India : open label phase II multicentre randomised controlled trial (PLACID Trial) | The BMJ
▻https://www.bmj.com/content/371/bmj.m3939

Échec, mais

The presence and levels of neutralising antibodies were not measured a priori

Monoclonal Antibody Trial Halted for Safety Concern | Brief19
▻https://brief19.com/2020/10/13/monoclonal-antibody-trial-halted-for-safety-concern

https://brief19.com/images/brief19.jpg

This news casts doubt as to the wisdom and safety of the approach used by President Trump’s medical team.

#anticorps_monoclonaux

Neuropathological Features of #Covid-19 | NEJM
▻https://www.nejm.org/doi/10.1056/NEJMc2019373

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/2020/nejm_2020.383.issue-10/nejmc2019373/20200828-01/images/img_small/nejmc2019373_t1.jpeg

Pas de lésions cérébrales inflammatoires ou d’autres types de lésions pouvant être attribuées au #sars-cov2
Présence du virus incertaine.

In conclusion, histopathological examination of brain specimens obtained from 18 patients who died 0 to 32 days after the onset of symptoms of Covid-19 showed only hypoxic changes and did not show encephalitis or other specific brain changes referable to the virus. There was no cytoplasmic viral staining on immunohistochemical analysis. The virus was detected at low levels in 6 brain sections obtained from 5 patients; these levels were not consistently related to the interval from the onset of symptoms to death. Positive tests may have been due to in situ virions or viral RNA from blood.

Neuropathology of patients with COVID-19 in Germany : a post-mortem case series - The Lancet Neurology
▻https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(20)30308-2/abstract

https://els-jbs-prod-cdn.jbs.elsevierhealth.com/cms/asset/953a1040-b516-4bd5-93cb-710aed4431d3/gr1.jpg

Ici des lésions inflammatoires sont retrouvées et la présence du virus semble indiscutable mais ne semble pas augmenter les lésions

43 patients were included in our study. Patients died in hospitals, nursing homes, or at home, and were aged between 51 years and 94 years (median 76 years [IQR 70–86]).

We detected fresh territorial ischaemic lesions in six (14%) patients.

37 (86%) patients had astrogliosis in all assessed regions.

Activation of microglia and infiltration by cytotoxic T lymphocytes was most pronounced in the brainstem and cerebellum, and meningeal cytotoxic T lymphocyte infiltration was seen in 34 (79%) patients.

SARS-CoV-2 could be detected in the brains of 21 (53%) of 40 examined patients, with SARS-CoV-2 viral proteins found in cranial nerves originating from the lower brainstem and in isolated cells of the brainstem. The presence of SARS-CoV-2 in the CNS was not associated with the severity of neuropathological changes.

[...]

In summary, our results show that SARS-CoV-2 RNA and proteins can be detected in the CNS. The brain shows mild neuropathological changes with pronounced neuroinflammation in the brainstem being the most common finding. However, the presence of SARS-CoV-2 in the CNS was not associated with the severity of neuropathological changes.16, 17 Careful neuropathological interpretation will be essential to disentangle which changes are attributable to SARS-CoV-2. All such changes must be mapped against neuropathological changes caused by pre-existing medical conditions often present in patients with COVID-19, as well as neuropathological changes caused by invasive treatments that are used in severe cases of COVID-19.35

Saliva** or Nasopharyngeal Swab Specimens for Detection of #SARS-CoV-2 | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMc2016359

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/2020/nejm_2020.383.issue-13/nejmc2016359/20200918/images/img_small/nejmc2016359_f1.jpeg

Rapporté en français ci-dessous :

Test de détection salivaire du SARS-Co V2 - Revue Médicale Suisse
▻https://www.revmed.ch/covid-19/Test-de-detection-salivaire-du-SARS-Co-V2

Un total de 70 patients hospitalisés atteints de #Covid-19 ont fourni le cadre de l’étude. Après confirmation de l’infection par un échantillon sur écouvillon nasopharyngé, des échantillons supplémentaires nasopharyngés et salivaires des patients ont été prélevés.

L’analyse a démontré la présence de plus de copies d’ARN du SRAS-CoV-2 dans les échantillons de salive que dans l’échantillon sur écouvillon nasopharyngés.

En outre, un pourcentage plus élevé d’échantillons de salive sont restés positifs au court du temps en comparaison avec les échantillons sur écouvillon nasopharyngé. Ces résultats suggèrent que les échantillons de salive ont au moins une sensibilité similaire que les échantillons sur écouvillon nasopharyngien dans la détection du SRAS-CoV-2 au cours de l’hospitalisation. L’analyse des variations de la concentration d’ARN au cours de l’évolution clinique a mis en évidence des fluctuations moins importantes dans la salive que dans les prélévements nasopharyngés.

Dans trois cas, un échantillon d’écouvillon nasopharyngé négatif a été suivi d’un écouvillon positif lors de la prochaine collecte d’un échantillon. Ce phénomène ne s’est produit qu’une seule fois avec les échantillons de salive.

L’étude s’est aussi intéressée à des personnes #asymptomatiques. 495 agents de santé asymptomatiques ont fourni du matériel pour tester à la fois des échantillons de salive et de nasopharynx. Sur 13 agents de santé positifs lors de l’examen salivaire, 9 avaient collecté des échantillons sur écouvillon nasopharyngien appariés le même jour, et 7 de ces échantillons se sont révélés négatifs Le diagnostic des 13 agents de santé a été confirmé par la suite par des tests diagnostiques d’échantillons nasopharyngés supplémentaires.

Commentaire

Les moyens de diagnostic évoluent et il est important de souligner un apport prometteur d’un prélèvement salivaire plus aisé à pratiquer et mieux accepté des patients que les frottis nasopharyngés actuels.

L’article du NEJM ajoute aussi que le choix de ce test permet aux services de santé de ne pas être débordés/exposés et est une réponse aux pénuries d’équipement de protection et de matériel de prélèvement,

Collection of saliva samples by patients themselves negates the need for direct interaction between health care workers and patients. This interaction is a source of major testing bottlenecks and presents a risk of nosocomial infection. Collection of saliva samples by patients themselves also alleviates demands for supplies of swabs and personal protective equipment. Given the growing need for testing, our findings provide support for the potential of saliva specimens in the diagnosis of SARS-CoV-2 infection.

Méthode d’auto-recueil de l’échantillon de salive :
▻https://www.nejm.org/doi/suppl/10.1056/NEJMc2016359/suppl_file/nejmc2016359_appendix_1.pdf

Saliva samples were self-collected by the patient using the methods described. Upon waking, patients were asked to avoid food, water and brushing of teeth until the sample was collected. Patients were asked to repeatedly spit into a sterile urine cup until roughly a third full of liquid (excluding bubbles), before securely closing it. All samples were stored at room temperature and transported to the research lab at the Yale School of Public Health within 5 hours of sample collection and tested within 12 hours of sample collection. While a stabilizing solution was not added to the saliva, recent work has demonstrated that SARS-CoV-2 RNA is stable in saliva stored at room temperature for up to 25 days.

#tests #salive #diagnostics

Rapid Decay of #Anti–SARS-CoV-2 Antibodies in Persons with Mild #Covid-19 | NEJM
▻https://www.nejm.org/doi/10.1056/NEJMc2025179

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmc2025179/20200724/images/img_small/nejmc2025179_f1.jpeg

COVID-19 : L’#immunité ne dure que 3 mois | santé log
▻https://www.santelog.com/actualites/covid-19-limmunite-ne-dure-que-3-mois

https://www.santelog.com/sites/santelog.com/www.santelog.com/files/images/accroche/cancer_du_pancreas_test_sanguin_3.jpg

Encore une fois, un titre et une interprétation qui supposent que l’immunité ne repose que sur les seuls #anticorps (#immunité_humorale).

Sur 80 participants volontaires post-COVID-19, les chercheurs ont suivi l’immunité de 20 femmes et 14 hommes rétablis de formes bégnines de la maladie. Des tests d’anticorps ont été réalisés en moyenne tous les 36 jours après les premiers symptômes de l’infection. L’analyse aboutit à ce déclin très rapide du taux d’anticorps, sur quelques semaines.
 
Si le rôle protecteur des anticorps contre le SRAS-CoV-2 reste à évaluer, ces anticorps sont généralement un corrélat de l’immunité antivirale, et les niveaux d’anticorps anti-domaine de liaison correspondent à l’activité plasmatique contre le virus. Dans cette étude, la désintégration précoce des anticorps est exponentielle (voir visuel ci-contre) et plus rapide que dans le cas du coronavirus SARS-CoV-1 (SRAS). Enfin, il est difficile d’extrapoler au-delà de la période d’observation d’environ 90 jours mais il est probable que la désintégration des anticorps ralentit ensuite.

#Hydroxychloroquine with or without #Azithromycin in Mild-to-Moderate Covid-19 | NEJM
▻https://www.nejm.org/doi/full/10.1056/NEJMoa2019014?query=C19&cid=DM95777_NEJM_Registered_Users_and_InActive&bid=234

https://www.nejm.org/na101/home/literatum/publisher/mms/journals/content/nejm/0/nejm.ahead-of-print/nejmoa2019014/20200723/images/img_medium/nejmoa2019014_f1.jpeg

Étude brésilienne, 504 patients,

CONCLUSIONS
Among patients hospitalized with mild-to-moderate #Covid-19, the use of hydroxychloroquine, alone or with azithromycin, did not improve clinical status at 15 days as compared with standard care.

#HCQ