Miquel Oliu‐Bartonab, Bary S.R. Pradelskic, Nicolas Woloszko

Pendant la pandémie de Covid‐19, les gouvernements ont utilisé différents instruments, incluant notamment les pass sanitaires certifiant du statut vaccinal, du rétablissement du Covid‐19 ou d’un test récent négatif, et requis pour accéder aux magasins, aux restaurants, aux écoles ou aux lieux de travail. Alors que les arguments pour ou contre ces pass sanitairesse sont concentrés sur la réduction de la transmission ou les inquiétudes éthiques, leur impact sur le taux de vaccination, la santé et l’économie reste à mesurer. Nous construisons ici des contrefactuels basés sur la théorie de la diffusion des innovations, et les validons économétriquement afin d’évaluer l’impact des incitations générées par les pass sanitaires en France, en Allemagne et en Italie.
Nous estimons que depuis leur annonce à l’été 2021 jusqu’à la fin de l’année, ces mesures ont permis une augmentation du taux de vaccination d’environ 13 points de pourcentage de la population totale en France, de 6,2 points en Allemagne et de 9,7 points en Italie. Les pass sanitaires ont permis d’éviter environ 4 000 décès en France (soit 32 % de plus), 1 100 en Allemagne et 1 300 en Italie. Ils ont réduit les pertes de PIB d’environ 6 milliards d’euros en France, 1,4 milliard d’euros en Allemagne et 2,1 milliards d’euros en Italie.

La mise en place des pass sanitaires a en particulier réduit la pression sur les unités de soins intensifs et, en France, a évité de dépasser les seuils d’occupation pour lesquels les confinements précédents avaient été déclenchés. Nos résultats sont quantitativement plus forts que ce qui avait été prédit et ils devraient aider les décisions sur le quand et comment de la mise en place des pass sanitaires pour augmenter le taux de vaccination et ainsi éviter des mesures plus restrictives, telles que les fermetures, confinements avec des conséquences économiques et sociales importantes.

Vittoria Colizza, épidémiologiste et directrice de recherche à l’Inserm, Sorbonne

Le passe vaccinal aura-t-il un impact sanitaire?
L’incitation a déjà fonctionné. Les primo-injections sont reparties à la hausse comme ça n’avait pas été le cas depuis longtemps. Elles réduisent de moitié le risque d’hospitalisation, donc avec un fort impact de prévention pour l’individu. La vaccination est indispensable. Les non-vaccinés pèsent de façon disproportionnée sur le système de soins. Trois variants ont dominé la France en un an. Chacun d’eux a mis en difficulté le vaccin, moins efficace face à un virus différent de celui contre lequel il a été conçu. Mais on voit que la dose de rappel booste la protection contre l’infection, qui tend à baisser dans le temps, et renforce celle contre les formes graves.

Pourquoi ne pas aller jusqu’à l’obligation vaccinale?
Les outils à utiliser pour inciter à la vaccination, comme pour les restrictions, dépendent du contrat social entre les autorités et la population, du contexte politique, de la culture d’un pays. En Italie, le gouvernement a instauré l’obligation vaccinale pour les plus de 50 ans, contrôlée par l’employeur. En France, une étude de l’Inserm a estimé que sur les 5 millions de non-vaccinés, deux tiers sont des opposants convaincus et un tiers hésite ou envisage de le faire. Ce sont eux qu’on doit aller chercher.

Une réduction de 20% de nos contacts sociaux diviserait par deux le nombre d’hospitalisations, selon l’Institut Pasteur

Si on était tous vaccinés, il n’y aurait plus de crise?
L’agence de sécurité sanitaire britannique estime que trois doses de vaccin confèrent une protection contre les formes graves autour de 90%. La protection contre l’infection symptomatique est estimée a 70% dans le premier mois après le booster, avec une diminution dans le temps (50% environ après trois mois). Mais des incertitudes persistent sur l’impact sanitaire qu’aura ce pic. D’un côté, on étudie encore ce variant découvert en novembre, il faut un certain temps pour élaborer des estimations avec confiance. De l’autre, cela dépend aussi de nos comportements. Une réduction de 20% de nos contacts sociaux diviserait par deux le nombre d’hospitalisations, selon l’Institut Pasteur.

Concrètement, comment fait-on?
On réduit le nombre de gens que l’on voit au cours d’une semaine ou on limite sa bulle sociale, en côtoyant toujours les mêmes. On évite une fête, un lieu bondé. Et on adopte le télétravail, qui a une vraie efficacité et réduit le risque d’infections. Mais une mesure isolée ne suffit pas.

Avec 24.000 Français hospitalisés, devrait-on s’inquiéter davantage?
Sur les admissions, on vient de dépasser le pic de la troisième vague, celle du variant Alpha au printemps 2021. Mais il faut regarder plusieurs indicateurs. Aujourd’hui, on a deux virus qui impactent de manière différente le système sanitaire et qui se côtoient à l’hôpital. Delta engendre des formes graves et continue à se propager ; les données suggèrent une baisse lente, mais attention, le protocole de criblage a changé donc on aura besoin de plus de temps pour confirmer cette tendance. Le variant Omicron, 90% des cas dans la moitié nord il y a une semaine, entraîne une probabilité de formes graves réduite de moitié par rapport à Delta et raccourcit les séjours en réanimation. La forte couverture vaccinale nous est indispensable. Mais avec un taux d’incidence très élevé, même une probabilité faible donnera lieu à un grand nombre d’hospitalisations. La vigilance s’impose.

Les données de ces derniers jours montrent un ralentissement de la dynamique de croissance, ce qui suggère qu’on est proche du pic de la courbe de cas détectés

Est-on proche du pic de cette vague?
Les données de ces derniers jours montrent un ralentissement de la dynamique de croissance, ce qui suggère qu’on est proche du pic de la courbe de cas détectés, en ligne avec les modélisations de l’Institut Pasteur. La survenue du pic variera selon les Régions. Par exemple, l’Ile-de-France connaît déjà une décrue de la courbe des nouveaux cas, à confirmer dans les jours à venir. De façon similaire, Londres avait anticipé le pic par rapport au reste du pays. On peut s’attendre à une décrue assez rapide, aussi à cause des propriétés du variant Omicron. C’est ce qu’on voit sur les dernières données du Royaume-Uni. Mais la dynamique sera impactée par nos comportements en termes de contacts, de mesures barrière, et d’injections de rappel.

La situation au Royaume-Uni reflète-t-elle encore ce qui se produira chez nous dans une semaine?
C’est sans doute l’exemple le plus proche, avec des différences. La population anglaise a acquis un niveau d’immunité plus élevé, et la couverture en doses de rappel est plus importante. En revanche, les adolescents sont moins vaccinés qu’en France et les enfants n’ont pas encore accès aux injections, même si cela reste minoritaire dans l’Hexagone. Au Portugal, plus de 40% des 5-9 ans vaccinés, comme au Danemark. En Espagne et en Autriche, c’est 20 à 25%.

Face à Omicron, faut-il revoir la stratégie de dépistage?
On a mis le système en tension, mais cette idée qu’il faut changer la politique de surveillance est trop liée au moment spécifique que nous vivons. Quand on passera le pic, ça va se calmer. D’ici là, face aux files devant les laboratoires, on pourrait envisager de tester en priorité les personnes à risque de forme grave ou de complication.

Ce que nous proposons, c’est de tester systématiquement tous les élèves une fois par semaine, deux fois par semaine lorsque l’incidence est élevée

Vous prônez depuis le début un dépistage systématique à l’école. Avec les autotests à répétition, on s’en approche?
Puisque le protocole scolaire reste de type réactif, avec une circulation virale très importante, ce n’est pas inattendu d’avoir une forte demande en tests. Tout cela va accroître la tension sur le système de dépistage et contraint à l’allègement des règles pour éviter de répéter les tests à trop de reprises. Ce système réactif nous condamne à courir après le virus, alors qu’on pourrait tester en prévention de façon plus proactive. La stratégie du dépistage systématique est, d’après nos résultats, plus efficace. Elle réduit la circulation virale, diminue le nombre de cas positifs et de jours d’école perdus. Autre avantage crucial en ce moment : elle permet de planifier la demande en autotests et donc leur stockage.

Espérez-vous enfin être entendue?
En tout cas, il y a un changement. Désormais, tout le monde pratique et connaît les autotests. Ce que nous proposons, c’est de tester systématiquement tous les élèves une fois par semaine, deux fois par semaine lorsque l’incidence est élevée. Les enfants l’accepteront peut-être mieux si c’est planifié. C’est un changement de paradigme dans la gestion du virus à l’école. Et c’est réalisable : l’Autriche le fait depuis début 2021 ; au Royaume-Uni, où les collégiens et lycéens ont deux tests hebdomadaires, le taux de reproduction du virus R à l’école secondaire est resté inférieur à 1 ; en Suisse, dans certains cantons, les petits de maternelle font un test salivaire par semaine ; aux Etats-Unis, près d’un quart de la population scolaire est testée systématiquement… En France, ce protocole serait surtout utile pour les élèves de primaire, très peu vaccinés.

La vague touche massivement les enfants. Cela vous inquiète?
Ce qui m’étonne, c’est de voir ces files d’enfants devant les pharmacies pour se faire tester. Dans d’autres pays, ils font la queue pour se faire vacciner! Aujourd’hui, on voit une hausse des hospitalisations pédiatriques, contre lesquelles la vaccination protège. Et elle a aussi un impact sur les contaminations. C’est un moyen supplémentaire de mettre en sécurité l’école, ce lieu qu’il faut garder ouvert.

Faut-il revenir à la fermeture des classes au premier cas, comme le réclament des syndicats d’enseignants?
On a estimé qu’on va mieux réduire le nombre de cas avec cette option plutôt qu’avec le dépistage réactif actuel. En revanche, on va augmenter largement le nombre de jours de classe perdus.

En extérieur, il faut faire attention dans les lieux bondés ou dans des conditions presque fermées, comme sur certaines terrasses

Les enseignants en école maternelle pourront recevoir des masques FFP2, est-ce utile?
Les expérimentations en laboratoire sur les gouttelettes émises, leur taille et leur aérosolisation ont montré que les FFP2 sont plus efficaces que les autres types de masques. Selon ces études, ils offrent une protection majeure pour le porteur, à condition qu’il le colle bien au visage, et pour les autres.

Le port du masque à l’extérieur est suspendu en Loire-Atlantique, à Paris, dans les Yvelines… A-t-il une utilité face à Omicron?
Il s’agit d’une question de bon sens. Le risque est plus élevé à l’intérieur surtout si on n’aère pas. En extérieur, il faut faire attention dans les lieux bondés ou dans des conditions presque fermées, comme sur certaines terrasses. Pour être efficace, il faut surtout le porter correctement, en couvrant le nez.

Certains disent que l’épidémie est finie. Et vous?
Cela me fait un peu sourire. J’ai souvent entendu ce refrain, mais cela ne s’est jamais encore produit. Des restrictions persistent, un nouveau variant plus dangereux peut émerger… On est encore en phase pandémique, et on n’a pas de preuve pour dire que cette vague sera la dernière.

Le virus est-il en passe de devenir endémique?
Ce sera le cas lorsqu’il circulera sur le modèle de la grippe qui revient chaque hiver, avec des flambées ponctuelles. C’est un scénario envisageable. Une des possibilités pour en arriver là serait que nous ayons superposé assez de “couches” d’immunité, par l’exposition au virus et grâce au vaccin, pour protéger la population des formes graves. Seuls les plus fragiles arriveraient alors à l’hôpital. En combien de temps ce scénario se met en place? Deux mois, deux ans? Aucun modèle mathématique ou historique ne le dit. La voie pour atteindre cet objectif n’est pas claire et nette comme une piste olympique. Elle ressemble plutôt à un parcours de trail, avec éventuellement plusieurs obstacles sur le chemin.

Enrico Bucci

In un ragionamento importante, in cui ha pure giustamente affermato che “Omicron non è come il raffreddore, il raffreddore non uccide”, l’immunologo Sergio Abrignani ha posto una domanda: “Siamo pronti in Italia, dopo il picco atteso per fine gennaio (quando la curva dei contagi dovrebbe scendere), a tollerare 3-4 mila decessi per Covid al mese per 4-5 mesi l’anno in cambio di una vita di nuovo ‘normale’?”.

 Come ben sa chi fa ricerca, porre le domande giuste è il vero motore del progresso della conoscenza; e per questo motivo, è importante anche riuscire a riconoscere le domande sbagliate. Vorrei qui spiegare al lettore perché, formulata in questo modo, la domanda di Abrignani è a mio parere sbagliata.

 Cominciamo dai punti più semplici. Delle due alternative prospettate fra cui si chiede di scegliere, una è definita in maniera piuttosto precisa: tollerare per 4-5 mesi 3-4 mila decessi per Covid-19. Nella loro apparente precisione, questi numeri sono in realtà del tutto arbitrari: innanzitutto, per la durata del periodo in cui bisognerebbe tollerare morti. Per esempio, nel 2021 i morti dovuti al Covid si sono distribuiti su un periodo di mesi ben più ampio, e l’eccesso di mortalità totale è durato oltre otto mesi; sebbene l’effetto della vaccinazione nel 2022 dovrebbe manifestarsi più intensamente che nell’anno precedente, quale sia la durata in mesi in cui sperimenteremo morti per Covid-19 è impossibile saperlo adesso.

Oltre a questo, le migliaia di morti cui dovremmo abituarci sono ancor meno definibili; per esempio, se immaginiamo di essere oggi al culmine di un periodo mensile di mortalità Covid, e proiettiamo simmetricamente nelle prossime due settimane i morti per Covid-19 osservati nelle due precedenti (un’assunzione fortemente riduttiva del numero reale di morti che osserveremo, visto che siamo lontani dal culmine dovuto a questa ondata), allora avremo circa 6.000 morti in un mese. Per non parlare di ulteriori variabili ignote, quali le caratteristiche di possibili nuove varianti.

Potremmo dire che, sebbene i numeri siano sbagliati, essi valgono solo come esempio (anche se c’è da dire che un esempio preso troppo al ribasso spinge verso certe scelte); vi è però un motivo più profondo, per cui la domanda è sbagliata per costruzione. La soglia che si è disposti a tollerare dipende dalle perdite che il Covid-19 ci arreca direttamente. Chi rischia di perdere il lavoro o l’impresa potrebbe voler tollerare anche 30.000 morti in un mese e un rischio diretto per la propria salute; chi ha parenti anziani o una patologia come il diabete (oltre 3 milioni di affetti in Italia), naturalmente, potrebbe avere un’idea molto diversa, visto che a morire preferenzialmente sono alcune ben determinate categorie. Cosa facciamo, comprimiamo i legittimi interessi di certe fasce di popolazione, per tutelare quelli di altre? Il parametro scelto per caratterizzare un’alternativa, evidentemente, è erroneo, perché la sua definizione quantitativa influenza in modo diverso le risposte di persone diverse.

 
Peraltro, la vita “normale”, cioè senza limitazioni di alcun tipo, con migliaia di morti non esiste, perché non si tiene conto delle centinaia di migliaia di infetti e della pressione sugli ospedali causata dai ricoveri, da una parte, e su tutte le istituzioni pubbliche a causa dei malati sintomatici, dall’altra; se si riempiono gli ospedali e contemporaneamente mancano per malattia sintomatica medici, infermieri, insegnanti eccetera, forse tanto “normale” la vita non può essere.

  
Vi è, tuttavia, un punto che a mio giudizio è il più importante di tutti: domande come quella di cui stiamo discutendo sono esempio di una fallacia ben nota, quella della falsa dicotomia o della falsa alternativa. Si suggerisce all’interlocutore, magari involontariamente, che vi siano solo le alternative contenute nella domanda, fra cui esercitare la scelta, eliminando dalla mente di chi deve rispondere tutte le altre possibili, e così spingendo verso le sole che interessano. Una vita da vaccinati, senza alcuna restrizione, con migliaia di morti, da una parte; e dall’altra una vita con meno morti (quanti?), con forti limitazioni delle proprie attività e delle proprie libertà. 

 
Oltre al fatto che, come abbiamo visto, per almeno una di queste due condizioni vi è il concreto dubbio che sia irrealizzabile, la cosa importante è che è possibile immaginare una serie infinita di alternative, in cui si adottino strategie più o meno severe di contenimento, e si realizzino numeri diversi di morti; tutte queste potrebbero essere opzioni sia più realistiche che preferibili rispetto alle uniche due suggerite, e scartarle a priori attraverso la formulazione di una domanda dicotomica è un buon artificio retorico, ma anche una fallacia di ragionamento riconosciuta fin dai filosofi dell’antica Grecia.

 
Sono sicuro che Sergio Abrignani non volesse affatto condizionare alcuno, così come sono certo della sua buona fede e intendo comunque ciò che in realtà è il suo messaggio, ovvero che non possiamo immaginare di impedire qualunque morte per Covid-19, comprimendo all’infinito la libertà delle persone; tuttavia, credo che il suo argomento meriti di essere meglio formulato, per evitare che sia invece utilizzato da chi, davvero in cattiva fede, vuole spingerci ad abbandonare ogni cautela e a rimuovere il virus dalla nostra mente.

Αντίθεση

.. Le malattie contagiose differiscono dalle altre malattie in modo sostanziale: sono per definizione, sociali. Presuppongono il contatto, la coesistenza, una comunità – per quanto alienata. Tuttavia, quello che la pandemia SARS-CoV-2 ci ha mostrato è come, nel periodo storico in cui ci troviamo, le relazioni sociali siano percepite come vuoto opprimente tra individui solidi, chiusi e inviolabili. Individualità autodeterminate, non negoziabili, non contagiose.

La critica radicale punta a smascherare il vuoto reale, in questo caso costituito proprio da questa individualità. La critica radicale percepisce le relazioni sociali come relazioni, cioè come connessioni tra persone, indipendentemente dal fatto che queste non siano prodotte e riprodotte liberamente e consapevolmente. Questo non impedisce loro di essere relazioni. Né dà credito all’idea che il nucleo centrale della realtà sociale sia l’individuo.

Criticare la gestione della pandemia negando la sua esistenza o il pericolo che comporta è esso stesso, a dir poco, un approccio catastrofico. Questo non è solo visibile nell’adozione acritica (e a volte inconscia) di cospirazioni reazionarie proto-fasciste; più importante forse, è come essa rifletta e promuova una comprensione estremamente distorta del capitale, dello Stato e del concetto di esistenza collettiva. Questo, di per sé, non rappresenta certo una novità all’interno della sinistra e degli ambienti radicali. Ma questa è forse la prima volta che queste distorsioni generano tali fratture esistenziali all’interno delle sue file.

Giacomo Gorini, Postdoctoral Antibody Immunologist at Jenner Institute, Oxford University

Ogni persona, al picco di infezione SARS-CoV-2, avrebbe all’interno del proprio corpo da 1 a 100 miliardi di particelle virali. Con 25 milioni di casi ora attivi nel mondo, ciò corrisponde a fino 2.5 miliardi di miliardi di virioni sulla Terra oggi.

Se assegnassimo un secondo ad ogni virione presente in una persona al picco di infezione, ci vorrebbero 3’171 anni per finire la conta di cento miliardi. Andando indietro nel tempo, torneremmo a quando Ramses III regnava l’Egitto, nel secolo in cui cadeva la città di Troia.

In tutto fino ad oggi sono stati registrati circa 280 milioni di casi, che porterebbero la conta a 28 miliardi di miliardi di particelle virali di SARS-CoV-2 mai esistite.

Considerato che ogni persona, al picco di infezione, porta circa 0.1 mg di virus nel corpo, oggi ci sono circa 2.5 kg di SARS-CoV-2 nel mondo e, dall’inizio della pandemia, ne sono esistiti circa 28 kg.

Tutto ovviamente basato su stime, con dovute approssimazioni – ad esempio, la differenza fra casi reali e registrati. Comunque, ho trovato interessante e curioso l’articolo su cui ho basato i calcoli (sperando di non avere sbagliato, ho controllato e ricontrollato!).

https://www.pnas.org/content/118/25/e2024815118

Giorgio Gilestro, Faculty of Natural Sciences, Department of Life Sciences, Imperial College, London

A. Evolution of the virus

It is fair to claim that the sars-Cov-2 development of 2021 has provided us with the largest experiment in evolution we have ever witnessed in the history of humankind. As it always happens with evolution, we know the rules and we can predict the outcome but the actual mechanisms are always an unpredictable black box. Evolution, if you want a bit of a nerdy quote, evolution is akin to deep-learning in computer science: we know the starting point and we can guess the final outcome but it is very difficult to predict and often even to recapitulate how we go from one point to the next.

A1. The most important variants have not developed linearly.

All of the most important variants – certainly all of those who became dominant – have not developed linearly from each other. Delta did not arise from Alpha and Omicron did not arise from Delta (or Beta). That was not a

SARS-CoV-2 Omicron variant - Wikipedia
Figure 1 – GISAID-based phylogenetic visualisation of the most important variants.

predictable development by any means but it does carry some important implications in terms of vaccinology. We knew Delta had acquired some decent properties of immune escape towards all the vaccines and in the Autumn of 2021 most scientists would have welcomed a vaccine update based on Delta’s Spike sequence, based on the assumption that any future variant would have evolved on Delta’s backbone. However, given how omicron evolved, it is now reasonable to assume that a Delta specific vaccine would not have helped towards omicron – in fact, it is even possible to speculate the opposite: a Delta specific vaccine may confer less protection toward omicron than the vaccines currently available! Looking at the early epidemiological findings from South Africa – where exposure to previous variants was rampant – it appears that the highest number of omicron re-infection were detected in people who had previously come in contact with Delta (Pulliam et al – Fig. 2b and pg 14). Other explanations for this observation are certainly possible (and in vitro data do not necessarily corroborate it: eg Ikemura et al) but it is something worth considering.

In general, it is clear that we cannot expect future variants to build on the backbone of the circulating one. In fact, from the immunological point of view, it makes sense to expect the opposite! Future variants will benefit from being as different as possible from the variant that just preceded them. The implications for future vaccines are important. We should probably enrich the antigen repertoire we will be using for future vaccines, to bet on multiple horses.

A2. The fitness landscape is large and dynamic.

This is something that comes as no surprise to anyone who has been looking at Sars-CoV-2 development from an evolutionary standpoint.

Visualization of a population evolving in a dynamic fitness landscape
Figure 2 – As the fitness landscape changes so does evolutionary pressure.

The first variants (Alpha, Delta) were selected against a very different landscape. Pressure for those was linked to their sheer contagious ability, not on immune escape. Omicron (with Lambda and Beta) on the other hand evolved in a different setting in which pressure was mostly towards immune evasion. Some had proposed that Delta represented “peak fitness” of the virus (Burioni et al) but, as population geneticists know well, it is not appropriate to talk about peak fitness when the fitness landscape changes continuously. What should we expect then? Given that immunity seems to be extremely short lasted, we should expect a continuous change of fitness landscape that will select new escape variants. The scenario is conceptually similar to what we see with flu but complicated by the outstanding evolutionary rate of this virus (see Kistler et al). Evolutionary rate is a function of population size and a month ago it would have been reasonable to assume that vaccines and

Figure 3 – Extremely high evolutionary pressure on S. Evolutionary rate of Sars-Cov-2 in the pre-vaccine phase was estimated to be 5x higher than the flu. Source Trevor Bedford.

immunity built by contagion would have slowed the pace of evolution. However, omicron spectacularly changed that prediction, considering that – at least for the sheer number of cases – the pandemic has never been as large as it will be with this variant. We should certainly expect that the virus now has a much larger evolutionary pressure towards immune escape and the evanescent nature of immune protection, with waining manifesting itself after a few weeks, creates perfect conditions for further selection.

A3. We cannot dismiss future reverse-zoonosis.

Where will future variants come from? Considering the molecular characteristics of omicron’s Spike and its likely geographical genesis, it is easily tempting to opt for its evolution in a chronically infected immunocompromised subject. However, the discovery of BA.2 (a sister branch of the original omicron sequence, now named BA.1) opened new perspectives. BA.1 and BA.2 are too different from each other for being vertical products of evolution; they have got to be horizontal. In lay terms: they are “sister variants” rather than “mother and daughter”. The implication is therefore for a “primordial broth of omicron” simmering in a wide reservoir. This reservoir is unlikely to be a single individual: it could be a group of immunocompromised patients or – equally possible – an animal reservoir. We know the Spike protein is extremely versatile when it comes to species affinity and animal reservoirs were identified both in captivity and in the wild: future reverse-zoonosis should not be dismissed with ease.

I would also command extreme caution towards the idea that the evolutionary landscape is restricted to ACE2 binding. We have multiple solid evidence of co-receptors and/or alternative receptors involved in cell entry of Sars-Cov-2 and we do know that other beta-coronaviruses do not use ACE2 at all (MERS-CoV, for instance, uses DPP4 as its main receptor). The unprecedented evolutionary pressure toward Spike implies that tropism could change and, with it, the disease profile (including symptomatology and the age/severity profile). The remarkable number of residues changes in the RBD of omicron’s Spike is an alarming sign that this could happen.

A4. The evolution of severity is a random walk.

We know the severity of the disease takes an unjustified level of attention with media and the public. Mathematically speaking, a more contagious variant is way more problematic than a more virulent one and yet we’ve seen with Alpha and Omicron the public being distracted by the red herring of severity. One aspect of omicron’s severity was not discussed as required: omicron descends from the original strain and therefore its severity should be compared to the original strain, not to Delta. Is omicron’s virulence higher or lower than the original Wuhan strain? Alpha doubled the risk of hospitalization compared to the original strain and Delta doubled the risk of hospitalization compared to Alpha. Omicron has evolved from the original strain, not from Delta, so the narrative of the virus getting milder is rather unsupported if we compare omicron severity to Delta’s severity.

B. Evolution of human response to the virus.

It is not just the virus to have evolved in this year. Our response has too – or at least it should have.

B1. Technology is paramount but wise politics is the most important tool.

Omicron has found most of the world incredibly unprepared. Many scientists spent the last two years explaining how important surveillance was, and yet most countries were completely in the dark when it came to identifying and monitoring omicron’s spread – and this despite the convenient and fortuitous fact that omicron BA.1’s contagion could be observed without sequencing, through SGTF. In Europe, only the UK and Denmark had a good understanding of omicron’s growth in December, with almost all other countries absolutely unaware of its pace and location. This was unfortunate for multiple reasons: different countries had different control measures in place and a comparison of omicron’s speed among different conditions could have hinted at whether some measures were more or less likely to dent its impressive growth.

Having said this, information about omicron itself did not influence dramatically the containment taken by the UK, mostly for political reasons. Little did it matter that the UK had daily data on omicron’s growth and the best epidemiological analysis of its spread and virulence with state of the art weekly reports and impressive numerology throughout.

While technology is paramount, politics is clearly the bottleneck.

B2. Easy vaccination vs difficult vaccination.

We would certainly be in a very different place had not been for vaccines and we have heard repeatedly how vaccines are the only way out from this mess. Paradoxically, however, very little effort has been placed toward extending vaccine protection to as many people as possible and most countries found themselves completely unprepared when facing vaccine sceptics. Positive persuasive efforts were extremely limited and/or based on outdated methods (for instance: no country has adopted a door-to-door salesman strategy) and punitive measures were preferred instead, with limited results. Judging on what we have witnessed so far, I am afraid we will probably see a wave of vaccine coercion in 2022 and there is no guarantee that will work at all; in fact, it may even lead to the opposite effect.

B3. What is the equilibrium we are seeking?

We will not be able to eradicate this virus and for years to come, we must accept some kind of equilibrium between its damage and what we intend as our normal routine. Where is that equilibrium? Do we measure it in terms of deaths of hospital capacity? Should the equilibrium be built on a potentiated health system? Should this threshold be decided democratically?

Containment measures with limited cost do exist and must be considered seriously. They range from increasing remote work to the widespread use of facemasks during the winter season. Many Asian countries have shown that while eradication is an impossible chimaera, containment is not.

What I would like to see in 2022.

Testing.

Omicron clearly showed that we cannot possibly win the rat race between viral evolution and human countermeasures. The virus is simply too fast. What we have not realised yet, however, is that the black swan of this pandemic is not the virus itself, but the unprecedented level of human connectivity we are experiencing at this time and age. It is absolutely possible and even likely that humankind has met in the past viruses with similar or even greater transmissibility but never in the history of humanity have connections been so immediate and widespread. Connectivity between countries and continents is what makes this pandemic unique and therefore those are the aspects we must try to curb. In all likelihood, it will be impossible to completely halt the spread of future variants but we must at least try to contain them. We have all learned to remove our shoes and laptops at security just before boarding a plane: we consider that normal routine (and even expected), so why not adopt something similar for covid? A LAMP test at the airport should be an integral part of the ticket we buy and we should make testing before travel and before social events more effortless and accessible.

Tracing.

As for tracing, we have not even tried. We have foregone any attempt of tracing technology in the name of perceived privacy and that was, in my opinion, a huge mistake. When it comes to movements and meetings, we have already surrendered most of our rights to privacy to advertising agencies, phone companies, and credit card providers so the choice of not even attempting digital tracing of contagion strikes me as a particularly irrational one.

A more genuine communication.

This is probably the least likely of my wishes but I would really love to see a more sincere scientific communication. I would like to see patronising and optimistic claims give way to sincere and realistic statements, about the virus, the vaccines, the political strategies and containment plans. Everything really has to start from here.

Kai Kupferschmidt

Going by what we know so far, places like Germany or the US are in for a world of trouble in the coming weeks.

So, I want to make a few general points here once that go beyond the science (will do the rest later):

Firstly, why are we in trouble?

Forget everything else for a moment and just look at the growth rate of omicron in places like Denmark and Norway. Look at London. This virus is moving fast. It spreads fast. And it will find those most vulnerable fast.

Unfortunately, places like Germany and the US still have a lot of vulnerable people who are unvaccinated.

This variant will find those people fast and if it is anything like previous variants it will make a significant portion of these people very, very sick.

Even if it turns out that omicron causes milder disease in unvaccinated people (which we have no way of knowing right now and no reason to assume), the sheer spread will likely eat up any advantage.

Add to that a lot of people sick and off work and hospitals already full…

As Bill Hanage told me: “There’s not much that can spread this fast and be benign to a society that’s already got full hospitals without it.”

I was reminded yesterday that I wrote a story last year called A divisive disease

Here’s the thing: This virus has always been good at dividing us (and we have damn sure made it easy for it at times). omicron will make those divisions even starker.

Within countries: in Germany we have 20-year-olds with no risk factors who are vaccinated and boosted. The individual risk to them is really, really low. We also have unvaccinated 70-year-olds with risk factors. So, the gap between those most and those least at risk has grown.

Between countries: some countries have rolled out highly protective vaccines for basically everyone and omicron is making them booster more and faster. Other countries are still struggling to get vaccines to give those most at risk their first shots.

The gap is growing.

The only solution to this is to realize that we are part of a community, a country, a world and that we cannot extricate ourselves from that web of interdependencies.

So, think things through starting at the end.

And then act accordingly.

I understand the frustration at the unvaccinated. I feel it.

But they are part of our community. If a lot of these people end up in hospital (plus lots of staff out sick), then healthcare is likely to collapse and that will affect you too. And your neighbour and your parents.

So, giving up simply is not an option.

We have to try and reach these people and we have to try and understand their fears and address them and we all have to work to build trust in each other.

But the truth is:

Whatever we do now in terms of vaccinating the unvaccinated, it won’t do anything for this rapidly building wave.

We are stuck with our collective (political, societal) failures and we will have to deal with it.

So, expect significant restrictions again.

Just remember:

It may feel like 2020 all over again, but your PERSONAL RISK if you are vaccinated and boostered is a LOT lower than it was then.

 Omicron presents a SOCIETAL RISK because it makes up for that by infecting many more people at once.

So, for many of us when we think about our own personal health and well-being the next weeks, we should concentrate more on how to stay connected to friends and family, how to stay active.

So: Talk to people, prepare, do things you enjoy, make plans for the summer, for after.

This is a really important point:

If you have people dear to you that are older or have comorbidities and that you cannot convince to get vaccinated, you can still impress on them how dangerous the next weeks will be for them and that they need to reduce contacts, wear masks etc.

One last point:

If – like me – you are vaccinated and boosted, you may still be worried about what is to come, you may be fearful for others and you may feel frustrated facing restrictions again amid this omicron wave.

But remember:

We are PRIVILEGED!

We are largely protected from severe disease.

We have access to life-saving tools many people in the world have been denied.

We have not been manipulated by those who know better into believing dangerous nonsense.

Let’s try and turn that privilege into something positive:

Let’s look out for others.

Let’s support those most in need of support in the coming weeks even if they made decisions we disagree with.

Let’s help people by spreading good information from trusted sources.

Nicolò Gozzi, Matteo Chinazzi, Jessica T. Davis, Kunpeng Mu, Ana Pastore y Piontti, Marco Ajelli, Nicola Perra, Alessandro Vespignani

Our results show that, as of 2021/07/05, vaccines averted 29,350 (IQR: [16,454-42,826]) deaths and 4,256,332 (IQR: [1,675,564-6,980,070]) infections and a new pandemic wave in the country. During the same period, they achieved a -22.2% (IQR: [-31.4%; -13.9%]) reduction in the IFR.

https://www.medrxiv.org/content/10.1101/2021.11.24.21266820v1?rss=1