Comparison of Saliva and Midturbinate Swabs for Detection of SARS-CoV-2

ABSTRACT Saliva is an attractive sample for detecting SARS-CoV-2. However, contradictory reports exist concerning the sensitivity of saliva versus nasal swabs. We followed close contacts of COVID-19 cases for up to 14 days from the last exposure and collected self-reported symptoms, midturbinate swabs (MTS), and saliva every 2 or 3 days. Ct values, viral load, and frequency of viral detection by MTS and saliva were compared. Fifty-eight contacts provided 200 saliva-MTS pairs, and 14 contacts (13 with symptoms) had one or more positive samples. Saliva and MTS had similar rates of viral detection (P = 0.78) and substantial agreement (κ = 0.83). However, sensitivity varied significantly with time since symptom onset. Early on (days −3 to 2), saliva had 12 times (95% CI: 1.2, 130) greater likelihood of viral detection and 3.2 times (95% CI: 2.8, 3.8) higher RNA copy numbers compared to MTS. After day 2 of symptoms, there was a nonsignificant trend toward greater sensitivity using MTS. Saliva and MTS demonstrated high agreement making saliva a suitable alternative to MTS for SARS-CoV-2 detection. Saliva was more sensitive early in the infection when the transmission was most likely to occur, suggesting that it may be a superior and cost-effective screening tool for COVID-19. IMPORTANCE The findings of this manuscript are increasingly important with new variants that appear to have shorter incubation periods emerging, which may be more prone to detection in saliva before detection in nasal swabs. Therefore, there is an urgent need to provide the science to support the use of a detection method that is highly sensitive and widely acceptable to the public to improve screening rates and early detection. The manuscript presents the first evidence that saliva-based RT-PCR is more sensitive than MTS-based RT-PCR in detecting SARS-CoV-2 during the presymptomatic period – the critical period for unwitting onward transmission. Considering other advantages of saliva samples, including the lower cost, greater acceptability within the general population, and less risk to health care workers, our findings further supported the use of saliva to identify presymptomatic infection and prevent transmission of the virus.

Findings: Neutralising antibody responses in reference sample pools sampled shortly after infection or vaccination were substantially less potent against the omicron variant than against wild-type SARS-CoV-2 (seven-fold to 42-fold reduction in ID50 titres).Similarly, for sera obtained before vaccination in 2020 from a cohort of convalescent hospital workers, neutralisation of the omicron variant was low to undetectable (all ID50 titres <20).However, in serum samples obtained in 2021 from two cohorts in Stockholm, substantial cross-neutralisation of the omicron variant was observed.Sera from 17 hospital workers after infection and subsequent vaccination had a reduction in average potency of only five-fold relative to wild-type SARS-CoV-2 (geometric mean ID50 titre 495 vs 105), and two donors had no reduction in potency.A similar pattern was observed in randomly sampled blood donors (n=40), who had an eightfold reduction in average potency against the omicron variant compared with wild-type SARS-CoV-2 (geometric mean ID50 titre 369 vs 45).We found that the omicron variant was resistant to neutralisation (50% inhibitory concentration [IC50] >10 μg/mL) by mAbs casirivimab (REGN-10933), imdevimab (REGN-10987), etesevimab (Ly-CoV016), and bamlanivimab (Ly-CoV555), which form part of antibody combinations used in the clinic to treat COVID-19.However, S309, the parent of sotrovimab, retained most of its activity, with only an approximately two-fold reduction in potency against the omicron variant compared with ancestral D614G SARS-CoV-2 (IC50 0•1-0•2 μg/mL).
Interpretation: These data highlight the extensive, but incomplete, evasion of neutralising antibody responses by the omicron variant, and suggest that boosting with licensed vaccines might be sufficient to raise neutralising antibody titres to protective levels.
Yen HL et al.

Lancet.
Transmission of SARS-CoV-2 delta variant (AY.127) from pet hamsters to humans, leading to onward human-to-human transmission: a case study.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8912929/pdf/main.pdf Abstract Background: Transmission of SARS-CoV-2 from humans to other mammals, including pet animals, has been reported.However, with the exception of farmed mink, there is no previous evidence that these infected animals can infect humans, resulting in sustained human-to-human transmission.Following a confirmed SARS-CoV-2 infection of a pet shop worker, animals in the shop and the warehouse supplying it were tested for evidence of SARS-CoV-2 infection.
Methods: In this case study, viral swabs and blood samples were collected from animals in a pet shop and its corresponding warehouse in Hong Kong.Nasal swab or saliva samples from human COVID-19 patients epidemiologically linked to the pet shop and from subsequent local cases confirmed to be infected by SARS-CoV-2 delta variant were collected.Oral swabs were tested by quantitative RT-PCR (RT-qPCR) for SARS-CoV-2 and blood samples were serologically tested by a surrogate virus neutralisation test and plaque reduction neutralisation test.The SARS-CoV-2 RT-qPCR positive samples were sequenced Studio che mira a dimostrare la possibile trasmissione del virus SARS-CoV-2 fra animali e uomo.Sono stati raccolti tamponi e campioni di sangue dagli animali di un negozio di animali e nel corrispondente magazzino di Hong Kong ; sno stati raccolti inoltre tampone nasofarigei o salivari di umani affetti da COVID-19 da virus delta legati epidemiologicamente al negozio di animali.La metà dei criceti siriani del negozio di animali e il 58% dei criceti siriani del rispettivo magazzino sono risultati positivi al virus.E' stata riscontrata una corrispondenza filogenetica fra il genoma di delta riscontrato nel criceto siriano e di quello riscontrato negli esseri umani epidemiologicamente legati criceti, con tuttavia alcuni gradi di eterogeneità.Da questo studio sembra confermarsi la capacità da parte del criceto siriano di infettarsi con il virus SARS-CoV-2, di poterlo trasmettere all'uomo e di generare quindi una trasmissione interumana.Questo lavoro rappresenta un ulteriore esempio a sostegno della teoria dello spill-over del virus SARS-CoV-2 da diverse specie animali all'uomo.by next generation viral full genome sequencing using the ISeq sequencing platform (Illumina), and the viral genomes were phylogenetically analysed.
Findings: Eight (50%) of 16 individually tested Syrian hamsters in the pet shop and seven (58%) of 12 Syrian hamsters in the corresponding warehouse were positive for SARS-CoV-2 infection in RT-qPCR or serological tests.None of the dwarf hamsters (n=75), rabbits (n=246), guinea pigs (n=66), chinchillas (n=116), and mice (n=2) were confirmed positive for SARS-CoV-2 in RT-qPCR tests.SARS-CoV-2 viral genomes deduced from human and hamster cases in this incident all belong to the delta variant of concern (AY.127) that had not been circulating locally before this outbreak.The viral genomes obtained from hamsters were phylogenetically related with some sequence heterogeneity.Phylogenetic dating suggests infection in these hamsters occurred around Oct 14, 2021 (95% CI Sept 15 to Nov 9, 2021).Multiple zoonotic transmission events to humans were detected, leading to onward human-to-human transmission.
Interpretation: Pet hamsters can be naturally infected with SARS-CoV-2.The virus can circulate among hamsters and lead to human infections.Both genetic and epidemiological results strongly suggest that there was more than one hamster-to-human transmission event in this study.This incident also led to onward human transmission.Importation of SARS-CoV-2-infected hamsters was a likely source of this outbreak.

Abstract
Saliva is an attractive sample for detecting SARS-CoV-2.However, contradictory reports exist concerning the sensitivity of saliva versus nasal swabs.We followed close contacts of COVID-19 cases for up to 14 days from the last exposure and collected self-reported symptoms, midturbinate swabs (MTS), and saliva every 2 or 3 days.Ct values, viral load, and frequency of viral detection by MTS and saliva were compared.Fifty-eight contacts provided 200 saliva-MTS pairs, and 14 contacts (13 with symptoms) had one or more positive samples.Saliva and MTS had similar rates of viral detection (P = 0.78) and substantial agreement (κ = 0.83).However, sensitivity varied significantly with time since symptom onset.Early on (days -3 to 2), saliva had 12 times (95% CI: 1.2, 130) greater likelihood of viral detection and 3.2 times (95% CI: 2.8, 3.8) higher RNA copy numbers compared to MTS.After day 2 of symptoms, there was a nonsignificant trend toward greater sensitivity using MTS.Saliva and MTS demonstrated high agreement making saliva a suitable alternative to MTS for SARS-CoV-2 detection.Saliva was more sensitive early in the infection when the transmission was most likely to occur, suggesting that it may be a superior and cost-effective screening tool for COVID-19.IMPORTANCE The findings of this manuscript are increasingly important with new variants that appear to have shorter incubation periods emerging, which may be more prone to detection in saliva before detection in nasal swabs.Therefore, there is an urgent need to provide the science to support the use of a detection method that is highly sensitive and widely acceptable to the public to improve screening rates and early detection.The manuscript Studio che compara il potere diagnostico del tampone molecolare su campioni di saliva con tampone molecolare su campione dei turbinati medi.Sono stati raccolti autonomamente dai partecipanti campioni appaiati di saliva e dei turbinati medi (200 campioni appaiati).Il tasso di detection virale è risultato simile per entrambi, con elevato agreement.E' stato tuttavia osservato che nella fase prodromica/sintomatica precoce (giorni da -3 a 2 rispetto allo sviluppo di sintomi) il campione salivare ha una capacità nettamente superiore di detection del virus e di riscontrare un numero più elevato di copie di RNA.Da questo studio sembrerebbe emergere un'ottima capacità diagnostica del tampone molecolare salivare che potrebbe rappresentare una valida alternativa, meno invasiva rispetto al tampone nasofaringeo, per lo screening di massa.La sua capacità diagnostica specialmente nelle fasi inizialissime dell'infezione virale, tenuto conto del rapidissimo tempo di incubazione delle nuove varianti virali, potrebbe fare del tampone salivare un prezioso strumento per la diagnosi precoce.
presents the first evidence that saliva-based RT-PCR is more sensitive than MTS-based RT-PCR in detecting SARS-CoV-2 during the presymptomatic period -the critical period for unwitting onward transmission.Considering other advantages of saliva samples, including the lower cost, greater acceptability within the general population, and less risk to health care workers, our findings further supported the use of saliva to identify presymptomatic infection and prevent transmission of the virus.
Background: The rapid spread of the SARS-CoV-2 Omicron (B.1.1.529)variant, including in highly vaccinated populations, has raised important questions about the efficacy of current vaccines.Immune correlates of vaccine protection against Omicron are not known.Methods: 30 cynomolgus macaques were immunized with homologous and heterologous primeboost regimens with the mRNA-based BNT162b2 vaccine and the adenovirus vector-based Ad26.COV2.S vaccine.Following vaccination, animals were challenged with the SARS-CoV-2 Omicron variant by the intranasal and intratracheal routes.Results: Omicron neutralizing antibodies were observed following the boost immunization and were higher in animals that received BNT162b2, whereas Omicron CD8+ T cell responses were higher in animals that received Ad26.COV2.S.Following Omicron challenge, sham controls showed more prolonged virus in nasal swabs than in bronchoalveolar lavage.Vaccinated macaques demonstrated rapid control of COMMENTO : studio condotto su 30 macachi cynomolgus immunizzati contro SARS -CoV2 con vari regimi di BNT162b2 e Ad26.COV2.S o un finto vaccino su cui sono state valutate le risposte anticorpali al baseline e che alla settimana 19 sono stati esposti a 10 6 PFU SARS-CoV-2 della variante Omicron per via intranasale e intratracheale.Quasi tutti gli animali vaccinati hanno avuto segno di infezione breakthrough nel BAL, ma con cariche virali sostanzialmente inferiori nei vaccinati rispetto ai controlli al giorno 2, con risoluzione dell'infezione per il giorno 4. Per quanto riguarda la via intranasale, tutti gli animali vaccinati hanno avuto segni di infezioni breakthrough nel secreto nasale, ma con cariche virali irrisorie per la maggior parte dei soggetti al giorno 4, fatto salvo per 2 individui del gruppo BNTx3 e 2 del BNTx2/Ad26, che hanno mostrato alti livelli fino al giorno 7, in maniera simili ai controlli.4 animali vaccinati con titoli anticorpali neutralizzanti elsevier.com%2Fretrieve%2Fpii%2FS009286742 2003348%3Fshowall%3 Dtrue virus in bronchoalveolar lavage, and most vaccinated animals also controlled virus in nasal swabs, showing that current vaccines provide substantial protection against Omicron in this model.However, vaccinated animals that had moderate levels of Omicron neutralizing antibodies but negligible Omicron CD8+ T cell responses failed to control virus in the upper respiratory tract.Virologic control correlated with both antibody and T cell responses.Conclusions: BNT162b2 and Ad26.COV2.S provided robust protection against high-dose challenge with the SARS-CoV-2 Omicron variant in macaques.Protection against this highly mutated SARS-CoV-2 variant correlated with both humoral and cellular immune responses.omicron-specifici moderati ma con risposta cellulare T CD8+ hanno fallito il controllo virale nel secreto nasale per il giorno 7. Questi dati suggeriscono l'importanza della risposta T CD8+ indotta dal vaccino, gettando luce sulla possible differenza tra i correlati di protezione contro la patologia severa e quelli contro l'infezione.la potenziale importanza delle risposte T indotte da vaccino potrebbe essere maggiore di quanto pensato nelle varianti come omicron che evadono la risposta umorale.In questo contesto, considerando quindi anche la prolungata durata dello shedding virale nell'alto tratto respiratorio dimostrata in questo studio, insieme come l'evasione dagli anticorpi neutralizzanti, potrebbe contribuire all'alto grado di trasmissibilita' della variante omicron.Background: Although clinical trials showed that vaccines have high efficacy and safety, differences in study designs and populations do not allow for comparison between vaccines and age groups.The objective of this study was to evaluate the effectiveness of vaccines against COVID-19 in real-world conditions in adults aged 60 years and older in Colombia.Methods: In this retrospective, population-based, matched cohort study, we evaluated the effectiveness of vaccines against COVID-19-related hospitalisation and death in people aged 60 years and older.The full cohort consisted of every person who was eligible to receive a COVID-19 vaccine in Colombia (the ESPERANZA cohort).The exposed cohort consisted of older adults who were fully vaccinated with Ad26.COV2-S, BNT162b2, ChAdOx1 nCoV-19, or CoronaVac, and who did not have a history of confirmed SARS-CoV-2 infection.The unexposed cohort were people aged 60 years CONTENUTO: Studio di coorte retrospettivo, populationbased, matchato per valutare l'efficacia dei vaccini nei pazienti over 60 nel prevenire le ospedalizzazioni COVIDrelate e morte in Colombia, includendo soggetti con schedula vaccinale completa tra 11 marzo 2021 e 26 ottobre 2021, quando la variante mu era prevalente nel paese.Si e' dimostrata un'alta efficacia, con un'efficacia totale per tutti i vaccnii del 61,6% nel prevenire l'ospedalizzazione, del 79,8% nel prevenire la morte dopo l'ospedalizzazione e 72,8% nel prevenire la mortalita' prima dell'ospedalizzazione.In questo studio, l'efficacia e' stata negativamente correlata all'eta', qualunque il vaccino sia stato impiegato : nelle eta' avanzate, i vaccini piu' efficaci sono stati quelli a vettore virale e mRNA rispetto ai vaccini a virus inattivato.Nelle fasce di eta' piu' anziane, come quelle dagli 80 anni in su, l'efficacia nel prevenire la mortalita' post ospedalizzazione si e' ridotta del 22,6% e 26,4% nella prevenzione della morte prima dell'ospedalizzazione.and older who had not received any dose of a COVID-19 vaccine during the study period.Participant follow-up was done between March 11, 2021, andOct 26, 2021.Vaccine effectiveness was estimated as 1-hazard ratio from causespecific proportional hazards models in the presence of competing risks.We estimated the overall effectiveness of being fully vaccinated, as well as effectiveness for each vaccine, adjusting by main potential confounders.The effectiveness of each vaccine was also assessed by age groups (ages 60-69 years, 70-79 years, and ≥80 years).Interpretation: All vaccines analysed in this study were effective at preventing hospitalisation and death from COVID-19 in fully vaccinated older adults, which is a promising result for the national vaccination programme against COVID-19 in Colombia and in countries where these biologics have been applied.Efforts should be improved to increase coverage LIMITI : sola variante mu circolante nel periodo studiato, vaccino CoronaVac favorito in questa fascia di eta' per maggiore diffusione e quantita' sul territorio, possibile autoselezione di gravita' dei pazienti non vaccinati (bias comportamentali), confondenti non noti, possibili ritardi nel registro vaccinazioni da cui gli studiosi hanno attinto e conseguente rischio di misclassificazione, dati incompleti sulla prima vaccinazione per una buona parte del campione, corto periodo di follow-up.among older adults.In addition, given that we observed that the effectiveness of vaccines declined with increasing age, a booster dose is also justified, which should be prioritised for older adults.
Infantino M. et al.

CCLM
The role of neutralizing antibodies by sVNT after two doses of BNT162b2 mRNA vaccine in a cohort of Italian healthcare workers https://www.degruyter.com/document/doi/10. 1515/cclm-2022-0170/html?lang=en Objectives: Evaluating anti-SARS-CoV-2 antibody levels is a current priority to drive immunization, as well as to predict when a vaccine booster dose may be required and for which priority groups.The aim of our study was to investigate the kinetics of anti-SARS-CoV-2 Spike S1 protein IgG (anti-S1 IgG) antibodies and neutralizing antibodies (NAbs) in an Italian cohort of healthcare workers (HCWs), following the Pfizer/BNT162b2 mRNA vaccine, over a period of up to six months after the second dose.
Methods: We enrolled 57 HCWs, without clinical history of COVID-19 infection.Fluoroenzyme-immunoassay was used for the quantitative anti-S1 IgG antibodies at different time points T1 (one month), T3 (three months) and T6 (six months) following the second vaccine shot.Simultaneously, a commercial surrogate virus neutralization test (sVNT) was used for the determination of NAbs, expressed as inhibition percentage (% IH).
Conclusions: Our findings reveal that the decrease of anti-S1 IgG levels do not correspond in parallel to a decrease of NAbs over time, which highlights the necessity of using both assays to assess vaccination effectiveness Moreira E.D. et al.

Safety and Efficacy of a Third Dose of BNT162b2
Covid-19 Vaccine https://www.nejm.org/doi/pdf/10.1056/NEJMoa2200674?articleTools=true BACKGROUND Active immunization with the BNT162b2 vaccine (Pfizer-BioNTech) has been a critical mitigation tool against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the coronavirus disease 2019 (Covid-19) pandemic.In light of reports of waning protection occurring 6 months after the primary twodose vaccine series, data are needed on the safety and efficacy of offering a third (booster) dose in persons 16 years of age or older.METHODS In this ongoing, placebo-controlled, randomized, phase 3 trial, we assigned participants who had received two 30-μg doses of the BNT162b2 vaccine at least 6 months earlier to be injected with a third dose of the BNT162b2 vaccine or with placebo.We assessed vaccine safety and efficacy against Covid-19 starting 7 days after the third dose.RESULTS A total of 5081 participants received a third BNT162b2 dose and 5044 received placebo.The median interval between dose 2 and dose 3 was 10.8 months in the vaccine group and 10.7 months in the placebo group; the median follow-up was 2.5 COMMENTO: Trial clinico controllato randomizzato di fase 3 (giugno-agosto 2021), finalizzato a valutare l'efficacia e la sicurezza di una terza dose booster di vaccino per Sars-CoV2 BNT162b2.In particolare, 5081 partecipanti allo studio hanno ricevuto una terza dose di vaccino e 5044 invece il placebo, almeno a 6 mesi dalle precedenti due dosi di vaccino Pfizer.Per quanto riguarda il profilo di sicurezza nel corso del followup (mediana di 2.5 mesi) non sono state riscontrate segnalazioni di nuove reazioni avverse, con la maggior parte delle reazioni di grado lieve e moderato, perlopiù correlate al sito di iniezione.Le reazioni avverse severe sono state riscontrate con maggiore frequenza nel gruppo dei vaccinati rispetto al placebo (0.5% vs 0.3%) Nessun caso di miocardite o pericardite è stato riportato.Per quanto riguarda l'efficacia della dose booster, nel gruppo ricevente il vaccino, solo 6 pazienti sono risultati positivi ad almeno una settimana dalla somministrazione.Viceversa, nel gruppo ricevente il placebo, sono stati 123 i casi di infezione da Sars-CoV2 segnalati.I dati finora acquisiti in fase 2-3 di questo trial mostrano una efficacia complessiva della dose booster del 90%, da 7 giorni fino a 6 mesi dalla somministrazione con una efficacia del months.Local and systemic reactogenicity events from the third dose were generally of low grade.No new safety signals were identified, and no cases of myocarditis or pericarditis were reported.Among the participants without evidence of previous SARS-CoV-2 infection who could be evaluated, Covid-19 with onset at least 7 days after dose 3 was observed in 6 participants in the vaccine group and in 123 participants in the placebo group, which corresponded to a relative vaccine efficacy of 95.3% (95% confidence interval, 89.5 to 98.3).CONCLUSIONS A third dose of the BNT162b2 vaccine administered a median of 10.8 months after the second dose provided 95.3% efficacy against Covid-19 as compared with two doses of the BNT162b2 vaccine during a median followup of 2.5 months 95.3% ad una mediana di 2.5 mesi di follow-up in pazienti senza storia di pregressa infezione.Non sono stati osservati casi di COVID-19 severo nel gruppo di pazienti vaccinati.Sicuramente i risultati preliminari dimostrano l'importanza e l'efficacia di una terza dose booster di vaccino, seppur in tal caso i dati riguardano un periodo storico in cui la variante predominate era la Delta, con limitazioni legate inoltre ai differenti tempi di ricezione della dose booster nella popolazione di studio e alla perdita di partecipanti nel gruppo placebo per permettere la ricezione della terza dose in casi speciifici. ) of patients after one year.There were no significant differences in the worsening of post-COVID 19 symptoms (22.7% vs 15.8%, p = 0.209) among vaccinated (n=132) and unvaccinated (n=347) patients.The presence of non-RBD SARS-CoV-2 IgG induced by natural infection showed a significant association with post-COVID-19 syndrome (OR 1.35, 95% CI 1.11-1.64,p = 0.003), and median non-RBD SARS-CoV-2 IgG titres were significantly higher in longhaulers than in patients without symptoms 22 (IQR 9.7-37.2) vs 14.1 (IQR 5.4-31.3)kAU/L, p = 0.009) after one year.In contrast, the presence of RBD SARS-CoV-2 IgG was not associated with the occurrence of post-COVID-19 syndrome (>2500 U/mL vs 0.9-2500 U/mL, OR 1.36, 95% CI 0.62-3.00,p = 0.441) and RBD SARS-CoV-2 IgG titres were similar in long-haulers than in patients without symptoms (50% values > 2500 U/mL vs 55.6% values > 2500 U/mL, p = 0.451) We have come a long way since the start of the COVID-19 pandemic-from hoarding toilet paper and wiping down groceries to sending our children back to school and vaccinating billions.Over this period, the global community of epidemiologists and evolutionary biologists has also come a long way in understanding the complex and changing dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19.In this Review, we retrace our steps through the questions that this community faced as the pandemic unfolded.We focus on the key roles that mathematical modeling and quantitative analyses of empirical data have played in allowing us to address these questions and Questa review sull'evoluzione dell'epidemiologia della pandemia di COVID-19 e sulle sfide da essa poste si concentra sui ruoli chiave che i modelli matematici e le analisi quantitative dei dati empirici hanno giocato nel permetterci di affrontare i vari interrogativi che via via ci siamo posti e nel provare a controllare la pandemia.Questi interrogativi, succedutisi nel corso di questi due anni vengono messi in correlazione, in questo lavoro, con le fasi della pandemia, ad esempio all'inizio del 2020 ci siamo chiesti se SARS-CoV-2 avesse il potenziale di causare una pandemia, oggi invece ci stiamo chiedendo : SARS-CoV-2 continuerà ancora ad evolversi per sfuggire all'immunità ?? Le domande sul vaccino si sono invece allargate a quelle riguardanti la misura in cui la vaccinazione potrebbe ridurre ultimately to better understand and control the pandemic.la trasmissione.

ECDC Technical Report
Considerations for the use of face masks in the community in the context of the SARS-CoV-2 Omicron variant of concern.
https://www.ecdc.europa.eu/sites/default/files /documents/Considerati ons-for-use-of-facemasks-in-thecommunity-in-thecontext-of-the-SARS-CoV-2-Omicron-variantof-concern.pdfA public health policy for wearing a face mask in public spaces should be considered in areas with community transmission when the public health objective is to limit community transmission.An additional option is to focus on the use of face masks in specific settings to protect people vulnerable to severe COVID-19, such as the elderly and people with underlying medical conditions.
• The appropriate use of face masks is important.The face mask should completely cover the face from the bridge of the nose down to the chin.The mask should be correctly adjusted on the bridge of the nose and to the face to minimise open space between the face and the mask.
• When community face coverings are used, it is advisable to choose coverings that comply with available standards for filtration efficacy and breathability, e.g.CEN CWA 17553.
• Respirators are expected to be more effective than medical masks, while community face coverings not manufactured according to the specifications in available guidelines for filtration efficacy and breathability are expected to be less effective than medical face masks.
Selecting the type of face mask should take into account Report aggiornato dell'ECDC sull'uso delle mascherine in comunità nel contesto epidemiologico attuale e dunque durante la diffusione della variante Omicron.
filtranti facciali rispetto alle mascherine chirurgiche in termini di riduzione della trasmissione di SARS-CoV-2 in contesti comunitari rimane molto limitata e inconcludente.Lancet Infect Dis https://www.thelancet.com/action/showPdf?pi i=S1473-3099%2822%2900069-X Background: By August, 2021, South Africa had been affected by three waves of SARS-CoV-2; the second associated with the beta variant and the third with the delta variant.Data on SARS-CoV-2 burden, transmission, and asymptomatic infections from Africa are scarce.We aimed to evaluate SARS-CoV-2 burden and transmission in one rural and one urban community in South Africa.
Methods: We conducted a prospective cohort study of households in Agincourt, Mpumalanga province (rural site) and Klerksdorp, North West province (urban site) from July, 2020 to August, 2021.We randomly selected households for the rural site from a health and sociodemographic surveillance system and for the urban site using GPS coordinates.Households with more than two members and where at least 75% of members consented to participate were eligible.Midturbinate nasal swabs were collected twice a week from household members irrespective of symptoms and tested for SARS-CoV-2 using real-time RT-PCR (RT-rtPCR).Serum was collected every 2 months and tested for anti-SARS-CoV-2 antibodies.Main outcomes were the cumulative incidence of SARS-CoV-2 infection, frequency of reinfection, symptomatic fraction (percent of infected individuals with ≥1 symptom), the duration of viral RNA shedding (number of days of SARS-CoV-2 RT-rtPCR Studio prospettico condotto in Sud Africa per studiare la trasmissione intra-familiare di SARS-CoV-2.
Lo studio ha evidenziato i limiti del fare affidamento esclusivamente su interventi non farmacologici.La vaccinazione rimane uno degli strumenti più importanti nella prevenzione della trasmissione.positivity), and the household cumulative infection risk (HCIR; number of infected household contacts divided by the number of susceptible household members).Interpretation: In this study, 565 (85•3%) SARS-CoV-2 infections were asymptomatic and index case symptom status did not affect HCIR, suggesting a limited role for control measures targeting symptomatic individuals.Increased household transmission of beta and delta variants was likely to have contributed to successive waves of SARS-CoV-2 infection, with more than 60% of individuals infected by the end of follow-up.
Background: Mortality statistics are fundamental to public health decision making.Mortality varies by time and location, and its measurement is affected by well known biases that have been exacerbated during the COVID-19 pandemic.This paper aims to estimate excess mortality from the COVID-19 pandemic in 191 countries and territories, and 252 subnational units for selected countries, from Jan 1, 2020, to Dec 31, 2021.
Methods: All-cause mortality reports were collected for 74 countries and territories and 266 subnational locations (including 31 locations in low-income and middle-income Questo lavoro, finanziato tra gli altri dalla Bill & Melinda Gates Foundation ha lo scopo di valutare le morti in eccesso -ovvero la differenza tra il numero di decessi registrati per tutte le cause e il numero previsto in base alle tendenze passate -per avere una misura del vero bilancio delle vittime della pandemia. Le prime stime globali peer-reviewed delle morti in eccesso indicano che, al 31.12.2021,18,2 milioni di persone potrebbero essere decedute a causa della pandemia di COVID-19, contro i 5,9 dichiarati.https://www.thelancet.com/action/showPdf?pi i=S0140-6736%2821%2902796-3 countries) that had reported either weekly or monthly deaths from all causes during the pandemic in 2020 and 2021, and for up to 11 year previously.In addition, we obtained excess mortality data for 12 states in India.Excess mortality over time was calculated as observed mortality, after excluding data from periods affected by late registration and anomalies such as heat waves, minus expected mortality.Six models were used to estimate expected mortality; final estimates of expected mortality were based on an ensemble of these models.Ensemble weights were based on root mean squared errors derived from an out-of-sample predictive validity test.As mortality records are incomplete worldwide, we built a statistical model that predicted the excess mortality rate for locations and periods where all-cause mortality data were not available.We used least absolute shrinkage and selection operator (LASSO) regression as a variable selection mechanism and selected 15 covariates, including both covariates pertaining to the COVID-19 pandemic, such as seroprevalence, and to background population health metrics, such as the Healthcare Access and Quality Index, with direction of effects on excess mortality concordant with a meta-analysis by the US Centers for Disease Control and Prevention.With the selected best model, we ran a prediction process using 100 draws for each covariate and 100 draws of estimated coefficients and residuals, estimated from the regressions run at the draw level using draw-level input data on both excess mortality and covariates.Mean Con 5,3 milioni di decessi in eccesso, l'Asia meridionale ha registrato il numero più alto di morti in eccesso stimate per COVID-19, seguita dal Nord Africa e dal Medio Oriente (1,7 milioni) e dall'Europa orientale (1,4 milioni).
Interpretation: The full impact of the pandemic has been much greater than what is indicated by reported deaths due to COVID-19 alone.Strengthening death registration systems around the world, long understood to be crucial to global public health strategy, is necessary for improved monitoring of this pandemic and future pandemics.In addition, further research is warranted to help distinguish the proportion of excess mortality that was caused by SARS-CoV-2 infection and the changes in causes of death as an indirect consequence of the pandemic.