Virus

Dr Stevanović: Još uvek ima teških slučajeva
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Danas zbog ubrzane detekcije i za[to ]što se pacijenti na vreme javljaju u Srbiji je malo težih kliničkih formi zbog koronavirusa, ali ih i dalje ima.

"Na infektvinoj klinici i dalje vidimo teške klinike slike", kaže.

Stevanović je naveo da su kapaciteti Infektivne klinike trenutno popunjeni dve trećine – od korona virusa se leče 73 pacijenta, a njih 12 je na intenzivnoj nezi i četiri su na respiratorima.

Vlada Srbije odlučila je na današnoj sednici da prihvati preporuke Kriznog štaba za borbu protiv korona virusa, tako da od sutra, 22. maja, za ulazak u Srbiju više nije potrebno imati negativan test na korona viurs, niti posebnu dozvolu kako za domaće, tako i za strane državljane, saznaje "Blic".

Takođe, više ne postoji mera upućivanja u samoizolaciju pri dolasku u Srbiju.

Krizni štab je ovo preporučio Vladi Srbije pre dva dana, a na osnovu analize trenutne epidemiološke situacije.

Based on new research results from the ongoing research on Covid-19 contagion on mink farms, it is plausible that a contagion from mink to humans has occurred. The research also shows that minks can have Covid-19 without showing symptoms of disease. Based on these latest insights, Minister Schouten of Agriculture, Nature and Food Quality and Minister De Jonge of Public Health, Welfare and Sport are taking a number of measures.

Minister Schouten: 'These new research results have a major impact on the owners, families and employees of mink farms as well as on local communities. I am therefore in close contact with all these parties involved'.

The virus that causes COVID-19 mutates relatively quickly. These changes in the genetic code can be followed. By comparing the genetic codes of the virus of different animals and humans a pedigree can be made and a picture can be obtained of how humans and animals have been infected in time and place. This type of research has also been done on infected minks and humans. One of the employees showed that the virus has similarities with the virus found on minks on the same farm. Based on the mutual comparison and the place of the virus in the pedigree, the conclusion from this investigation is that it is plausible that one employee of an infected mink farm was infected by minks.

In order to clarify this, the researchers are currently further mapping the 'genetic pedigree' of infected people in the vicinity of the infected mink farm in question in order to obtain as complete a picture as possible.

RIVM has indicated that the risk of people being exposed to the virus outside the stable is still negligible. The RIVM previously carried out this risk assessment on the basis of the fact that the research showed that all air and dust samples outside the stable did not contain any virus during repeated measurements.

Repriza
Sofija Mandić20/05/2020

Zabrinjavajuća je jučerašnja preporuka Kriznog štaba upućena Vladi Srbije. Ovo telo je, prema navodima medija, preporučilo da od petka, 22. maja, za ulazak u Srbiju ne bude potreban negativan test na korona virus, niti posebna dozvola za domaće ili strane državljane. Ova preporuka navodno treba da bude potvrđena u četvrtak na sednici Vlade. To nam daje dovoljno vremena da pokušamo možda i nemoguće – da urazumimo takozvani Krizni štab i Vladu Srbije.

Krizni štab je ovde etiketiran kao takozvani jer nikada nismo saznali poreklo ovog tela. Ko ga je osnovao i u kom svojstvu? Zakon o zaštiti stanovništva od zaraznih bolesti predviđa osnivanje Republičke stručne komisije za zaštitu stanovništva od zaraznih bolesti, koju do dana današnjeg nismo upoznali. Zadatak ove komisije je utvrđivanje stručnih stavova o očuvanju i unapređenju zdravlja; sprečavanju i suzbijanju zaraznih bolesti; lečenju i zdravstvenoj nezi kao i o unapređenju i razvoju organizacije zdravstvene službe koja se bavi prevencijom, suzbijanjem, lečenjem zaraznih bolesti; podrškom obolelima zasnovanom na dokazima i međunarodnim preporukama. Dakle, sve ono što je od kraja februara, pa sve do danas, činio takozvani Krizni štab.

Vratimo se sada preporuci Vladi Srbije. Izgleda da su se i Krizni štab i Vlada uživeli u izdavanje dekreta kojima dopuštaju ili pak, pod pretnjom drakonskim kaznama i javnom pogrdom, zabranjuju određena ponašanja.

Poslednja preporuka bi, čini se, trebala da doprinese prividu ubrzanog povratka na staro, a sve u isključivu svrhu izborne normalizacije. Manipulacija može dobro da posluži kako za birače koji su preživeli dvomesečni cunami vanrednog stanja u Srbiji, tako i za one koji planiraju da dođu u zemlju i eventualno glasaju na izborima koji će se održati 21. juna. Ne bi bilo zgodno da pridošli birači budu zaustavljeni na granici, stavljeni pod zdravstveni nadzor ili – daleko bilo – u karantin.

To što će putnici na ulasku u zemlju dobiti „zdravstveno upozorenje u kome se navodi da ulaze na teritoriju na kojoj virus još cirkuliše“, samo je eufemizam za činjenicu da putnici ulaze na teritoriju koja je u epidemiji. Ali zapravo, svima nam je jasno da nije toliko važno gde dolaze, već odakle dolaze.

Imajući to u vidu, veliki problem predstavlja to što zakon nalaže sve suprotno od onoga što je takozvani Krizni štab preporučio Vladi. Bez obzira na bilo koju drugu okolnost, pa čak ni na onu da li je epidemija određene bolesti proglašena u Srbiji, osobe sa ili bez zdravstvenih tegoba koje dolaze iz zemalja u kojima ima oboljenja koja predstavljaju pretnju po međunarodno javno zdravlje ili u kojima postoji epidemija i rizik od oboljevanja od zaraznih bolesti koje se mogu uneti u zemlju, dužna su da se na graničnom prelazu prijave nadležnoj zdravstvenoj službi, odnosno organima nadležnim za kontrolu prelaženja državne granice kao i da se u mestu boravka jave nadležnom zavodu, odnosno institutu za javno zdravlje za određivanje zdravstvenog nadzora.

Nešto stroža mera karantina, kojom se ograničava i sloboda kretanja putnika, određuje se zdravim licima koja su bila ili za koja postoji sumnja da su bila u kontaktu sa licima obolelim od zaraznih bolesti ili sa licem za koje postoji sumnja da je obolelo od zarazne bolesti.

Dakle, imamo dva zakonska nivoa intervencije prilikom prelaska državne granice – jedan se odnosi na ulazak u zemlju iz druge zemlje u kojoj ima oboljenja koja predstavljaju opasnost po javno zdravlje ili u kojima je proglašena epidemija. U ovom slučaju je dovoljno da samo dolazite iz zemlje u kojoj je rasprostranjena bolest (što je u ovom trenutku većina evropskih zemalja) i to vas direktno vodi dužnosti prijave nadležnim organima.

Drugi nivo zakonske intervencije se odnosi na osobe za koje postoji sumnja konkretnije prirode, da su bili u kontaktu sa zaraženom ili moguće zaraženom osobom.

To što nekakav Krizni štab nekakvoj Vladi preporučuje bilo šta mimo procedura regulisanih Zakonom o zaštiti stanovništva od zaraznih bolesti je potpuno irelevantno, a dalekosežno i opasno, kako za pojedince, tako i za javno zdravlje.

Kako se dalje ne bi sramotila u „upravljanju“ krizom, za Vladu bi bilo najbolje da preporuku Kriznog štaba ignoriše, a putnike uputi na postojeće zakonske procedure. Ovo bi bilo dobro učiniti, iako imamo razloga da verujemo da je Vlada, na sebi svojstven način, zapravo i naručila preporuku Kriznog štaba.

To nas vraća sada već čuvenoj izjavi prof. dr Kona da njemu „nije zanimljivo pitanje“ da li u Srbiji važe zakoni naše zemlje. Sada iznova dolazimo do zaključka da je to ne samo zanimljivo, već možda i ključno za dalji razvoj epidemije od većeg epidemiološkog značaja koja je na snazi u Srbiji, bez ozbiljnijih izgleda da se ugasi do 21. juna.

Pravna preporuka građanima koji će posle 22. maja ući u zemlju iz zemalja u kojima je epidemija korona virusa na snazi jeste da se obavezno jave nadležnim graničnim i epidemiološkim službama, bez obzira šta o tome u četvrtak izjavi Vlada. Ona se očigledno nije oporavila od bunila i divljanja tokom vanrednog stanja.

U suprotnom, za svega nekoliko dana možemo gledati reprizu lova na pridošlice, uključujući i njihovo prekršajno i krivično kažnjavanje. Nadam se da će ovu preporuku građani poslušati i da neće dozvoliti da se, svega dva meseca od početka epidemije, ponovo nađemo na početku nasilničkog ciklusa, predvođenog državom i njenim ljutitim čelnicima.

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EKSKLUZIVNO Hrvatska stručnjakinja i direktorica Klinike za infektivne bolesti ''Dr. Fran Mihaljević'' u Zagrebu

Alemka Markotić za "Avaz": Virus bi se mogao vratiti najesen

Možemo karakterizirati virus koji se kreće na ovim prostorima i tako možemo pomoći u razvoju kliničkih studija za vakcine i lijek

A. Tiro / Avaz.ba
28.04.2020 20:45

Sve zemlje regiona, s izuzetkom Srbije, drže se dosta dobro u borbi protiv koronavirusa, ocijenila je u razgovoru za „Avazu“ direktorica Klinike za infektivne bolesti ''Dr. Fran Mihaljević'' u Zagrebu, dr. Alemka Marković.

Virus u cirkulaciji

- I u Srbiji će situacija oko virusa brzo doći pod kontrolu. Sve stare epidemiološke mjere koje su naši učitelji razradili na ovim prostorima pokazale su se dobrima. U Hrvatskoj smo epidemiju stavili pod kontrolu, ali to nije razlog za opuštanje. Mora se znati da je virus i dalje u cirkulaciji i da smo uspjeli ograničiti njegovo širenje samo zato što smo se držali svih mjera - govori Markotić.

Ističe da bi se situacija pogoršala ukoliko se popusti s mjerama.

- Ne smijemo izgubiti iz vida da se kapljični virusi mogu javljati i sezonski, tako da moramo misliti da bi se najesen mogao ponovo vratiti u isto vrijeme kada i gripa. Ali definitivno ćemo ove epidemiološke mjere jedno duže vrijeme prakticirati - potcrtava.

Kao izuzetno važnu stvar ističe činjenicu da su hrvatski doktori i naučnici uspjeli izolirati virus.

- Možemo karakterizirati virus koji se kreće na ovim prostorima i tako pomoći u razvoju kliničkih studija za vakcine i lijek, pratiti uspješnost liječenja, odrediti da li ljudi imaju zaštitna antitijela u svojoj krvi. Ono što smo naučili, zajedno s ostalim stručnjacima iz svijeta, jeste da je to virus koji je dao cijeli niz neobičnih situacija - pojašnjava Markotić.

Ljeto i sunce

Dodaje da se, teoretski, virus neće usporiti zbog ljetne temperature i sunca.

- Jednostavno, tokom ljeta ljudi nisu nagurani u zatvorenom prostoru, više se domovi provjetravaju, mnogi će biti na godišnjim odmorima i sve to smanjuje mogućnost širenja virusa na jedan način. Ipak, ne smijemo se samo pouzdati da će ljeto i sunce potpuno neutralizirati virus - naglašava naša sagovornica.

Kada je u pitanju učinkovit lijek, odnosno vakcina za koronavirus, doktorica govori da bi on mogao doći za godinu.

- To će biti ako budemo imali sreće, mada neki obećavaju i ranije. Možemo imati prve informacije da se u prvoj fazi kliničkih studija pokaže da je lijek učinkovit, da nema nuspojava i to bi nas moglo ohrabriti. Međutim, postoji druga i treća klinička faza - objašnjava Markotić.

Događaji iz Sarajeva

Dr. Markotić ističe kako se „očeličila“ tokom rata u Sarajevu, gdje je radila kao doktorica, i to joj je iskustvo pomoglo da ne osjeti strah nakon uvođenja vanrednog stanja zbog pandemije koronavirusa.

- Svako ko je proživio rat bilo gdje u svijetu, pa i u Sarajevu, shvati najgore što čovjek drugom čovjeku može napraviti. Sve te situacije su me sigurno očvrsnule, tako da niti u jednom momentu nisam strahovala od vanrednih mjera - zaključuje Markotić.

Doubts over Oxford vaccine as it fails to stop coronavirus in animal trials
Experts warn that vaccine may only be 'partially effective' after results of a trial in rhesus macaque monkeys

BySarah Newey, GLOBAL HEALTH SECURITY REPORTER and Paul Nuki, GLOBAL HEALTH SECURITY EDITOR, LONDON18 May 2020 • 12:43pm
The Oxford University vaccine tipped as a "front runner" in the race to develop a coronavirus jab does not stop the virus in monkeys and may only be partially effective, experts have warned.

A trial of the vaccine in rhesus macaque monkeys did not stop the animals from catching the virus and has raised questions about the vaccine's likely human efficacy and ongoing development.

The vaccine, known as ChAdOx1 nCoV-19, is undergoing human trials in Britain. The Government has brokered a deal between Oxford University and the drug company AstraZeneca to produce up to 30 million doses if it proves successful, having ploughed £47 million into the research.

"All of the vaccinated monkeys treated with the Oxford vaccine became infected when challenged as judged by recovery of virus genomic RNA from nasal secretions," said Dr William Haseltine, a former Harvard Medical School professor who had a pivotal role in the development of early HIV/Aids treatments.

"There was no difference in the amount of viral RNA detected from this site in the vaccinated monkeys as compared to the unvaccinated animals. Which is to say, all vaccinated animals were infected," Dr Haseltine wrote in an article on Forbes. 

Jonathan Ball, professor of molecular virology at the University of Nottingham, said the vaccine data suggests that the jab may not be able to prevent the spread of the virus between infected individuals.   

"That viral loads in the noses of vaccinated and unvaccinated animals were identical is very significant. If the same happened in humans, vaccination would not stop spread," he said. "I genuinely believe that this finding should warrant an urgent re-appraisal of the ongoing human trials of the ChAdOx1 vaccine."

The trials investigating the immune response to the Oxford vaccine in rhesus macaque monkeys were carried out at the National Institute of Health's Rocky Mountain Laboratory in the US, with initial results published in a press release at the end of April. 

The results were said at the time to be encouraging, but publication of the full trial results last week showed the vaccine did not prevent the animals catching the virus, although there was evidence it may reduce the severity.

This is in contrast to a Chinese vaccine trial in April that did appear to stop the development of Covid-19 in monkeys. That trial, by Sinovac Biotech, a privately held Beijing-based company, used a modified version of the full Sars-Cov-2 virus in its vaccine, while the Oxford vaccine uses a common cold virus to try and provoke an immune response.  

In the Oxford monkey trial, six monkeys were infected with single doses of ChAdOx1 nCoV-19 and exposed to coronavirus. A control group of three non-vaccinated monkeys were also infected. Both the immunised and non-immunised monkeys were then monitored for seven days for signs of developing Covid-19. 

One measure of infection is an increased breathing rate as the virus attacks the lungs – three of the vaccinated animals displayed this symptom. On autopsy, the researchers found the virus in the vaccinated monkeys' lungs.

On the upside, none of the vaccinated monkeys displayed pneumonia which suggests that, while not stopping the virus, it may be partially protective.

Dr Haseltine said this was "encouraging", but that "experience with other vaccines tells us that is not a firm guarantee that such will be the case for humans".

"It is crystal clear that the vaccine did not provide sterilising immunity to the virus challenge, the gold standard for any vaccine. It may provide partial protection," he said.

The doubts about the vaccine come after Alok Sharma, the Business Secretary, said that the speed at which Oxford was pushing ahead with development was "genuinely unprecedented" and that the first clinical trials were "progressing well".

Mr Sharma also announced £84 million of additional funding to further accelerate the vaccine research at Oxford University and another UK vaccine candidate being developed by Imperial College. The following graphic shows how scientists are trying to produce a vaccine:



Separate funding was announced for a UK vaccine manufacturing capacity – the Vaccines Manufacturing and Innovation Centre – in Oxford. This will be able to manufacture a range of vaccines depending on what works.

Despite the findings, there is still "cautious optimism" about the Oxford vaccine among some experts. In the study all of the animals administered with a single shot of the vaccine generated antibodies against the virus within 28 days. 

"The most important finding to me is the combination of considerable efficacy in terms of viral load and subsequent pneumonia, but no evidence of immune-enhanced disease," said Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine. 

"It is encouraging to see these results and suggests cautious optimism for the Oxford vaccine trial being done in humans."

Dr Penny Ward, a visiting professor in pharmaceutical medicine at King's College London, said: "Single doses of the vaccine produced high quantities of neutralising antibody in both species. 

"It is helpful to see that monkeys vaccinated with this Sars-CoV-2 vaccine did not have any evidence of enhanced lung pathology and that, despite some evidence of upper respiratory tract infection by Sars-Cov-2 after high viral load virus challenge, monkeys given the vaccine did not have any evidence of pneumonia."

But Eleanor Riley, professor of Immunology and Infectious Disease at the University of Edinburgh, said there was both good and bad news in the most monkey trials:

“Whilst the vaccine induced neutralising antibodies and vaccinated animals experienced less severe clinical symptoms than unvaccinated animals (good), the neutralising antibody titres were low and insufficient to prevent infection and – importantly – insufficient to prevent viral shedding in nasal secretions (worrying).

“If similar results were obtained in humans, the vaccine would likely provide partial protection against disease in the vaccine recipient but would be unlikely to reduce transmission in the wider community.”

Radovanović odgovara Konu: Prošli smo najgore u regionu

https://nova.rs/drustvo/radovanovic-odgovara-konu-prosli-smo-najgore-u-regionu/

Iznenadilo me je vraćanje kolege Kona na bajatu i neaktuelnu dilemu: vanredno stanje ili vanredna situacija. Od dr Kona i Kriznog štaba javnost je očekivala odgovor na bar dva ključna pitanja – kako ne mogu da se slože da li su potrebne maske i kako pravdaju kontroverznu odluku o jednostranom otvaranju granica, napisao je prof. dr Zoran Radovanović u autorskom tekstu objavljenom u listu Danas.

Radovanović je na taj način ogovorio na na objavu dr Predraga Kona na Fejsbuku, koja je na našem sajtu objavljena pod naslovom Kon: Znam o propustima više od bilo koga, pisaću o tome.

Odgovor prenosimo u celosti:

1. Nesporna je tvrdnja dr Kona da bi bez preduzimanja mera broj žrtava kovida 19 u Srbiji bio mnogo veći od zvanično evidentiranih skoro 250. Isto zapažanje važi za ceo svet. Valja, međutim, uočiti da smo prošli najgore u regionu: imali smo najrigoroznije mere, a najvišu stopu obolevanja. Ta nesrazmera je utoliko upadljivija što smo pribegavali vrlo restriktivnim kriterijumima za testiranje, zbog čega su, bar prvih sedmica, mnogi bolesnici sa tipičnom ili skoro tipičnom slikom bolesti ostajali netestirani.

2. Srbija je uporno ignorisala upozorenja Svestske zdravstvene organizacije o potrebi da se sve zemlje članice pripreme za očekivanu pandemiju, pa ju je dočekala nespremno, kao i poplavu 2014. godine i kao što će, bojim se, biti slučaj i u budućnosti. Zato nas je profesorka Markotić, direktorka Klinike za zarazne bolesti u Zagrebu, nedavno označila kao jedini negativni primer u regionu. Ova konstatacija ide na račun države, a istovremno predstavlja priznanje Kriznom štabu zbog uslova pod kojima je radio.

3. Greši kolega Kon kad pomišlja da smo „ljudi koji pojma nemaju u kakvoj situaciji je započela pandemija“. Na osnovu kreveljenja tokom one sramne konferencije za štampu 26. februara svima je jasno da je pandemija započela u atmosferi potpune ignorancije. Konu sam ranije odao priznanje što se tada držao dostojanstveno, uz samo jedan usiljeni smešak. (Grešan sam što nikada nisam pohvalio profesora Vladimira Petrovića, našeg najvećeg radno aktivnog poznavaoca epidemiologije zaraznih bolesti, koji se i tada i kasnije tako uspešno sklanjao da malo ko zna za njegovo članstvo u Kriznom štabu.)

4. Zapanjen sam saznanjem da kolega Kon veruje kako proglašenje epidemije od većeg epidemiološkog značaja (čitaj: vanredne situacije) navodno dopušta samo davanje preporuka. Istina je da po čl. 52 zakona koji svim epidemiolozima mora da bude dobro poznat ministar zdravlja može da naredi zabranu okupljanja, ograničenje kretanja, zabranu ili ograničenje putovanja, vanrednu vakcinaciju itd. Takođe je ovlašćen da naredi obavezno učešće pravnih lica, preduzetnika i građana u suzbijanju zarazne bolesti. Razlika između vanrednog stanja (koje se, inače, proglašava kada je u pitanju opstanak države) i vanredne situacije samo je u tome što u prvom slučaju na ulice izlazi vojska sa dugim cevima i što mogu da se odlože izbori, dok u drugom slučaju o sprovođenju zabrana i drugih mera brine policija.

5. Dr Kon pogrešno misli i da nisu mogle „da se sprovode razne vrste neophodnih nabavki samo sa proglašenjem epidemije“. Vanredna situacija, kao i vanredno stanje, dopušta direktne nabavke, bez tendera i drugih ograničenja. (Uzgred, treba li podsećati na „Krušik“ i slične primere kao dokaz da kod nas ni u redovnim okolnostima slične „formalnosti“ ne moraju da važe?)

6. Moja navodna zabluda od pre 10 godina odnosi se na kritiku postupanja tokom pandemije svinjskog gripa. Tada je tenderom nabavljena sporna vakcina preko niza posrednika, zastupnika i predstavnika. Da je ranije, a ne samo dan-dva pre potpisivanja ugovora, proglašena vanredna situacija (šta se čekalo do novembra?), do vakcine je moglo da se dođe direktno, za mnogo manje para.

7. Slažem se da je tadašnja direktorka Fonda za zdravstveno osiguranje nevina čamila u zatvoru. Proces nabavke vakcina ide na dušu nadležnog ministra zdravlja.

8. Epidemija variole 1972. godine uspešno je suzbijena proglašenjem vanredne situacije (iz posebnih razloga izuzetak je predstavljala teritorija KiM). Mere zabrana su bile oštre i sprovođene su po zakonu koji se od tada nije bitno menjao.

9. O dovoljnosti i primerenosti vanredne situacije nastaloj pretnji usled kovida 19 izjašnjavali su se i lekari i pravnici. Stekao sam utisak da je, uz retke izuzetke, u tom pogledu postignuta opšta saglasnost. Ništa nas ne sprečava da razgovor nastavimo u stručnim krugovima, kada sve prođe. To će biti prilika da otvoreno razmotrimo i propuste nagoveštene u oba naslova.

The Lancet publishes results of phase 1 human trial of CanSino Biologics #COVID19 vaccine in 108 subjects: https://t.co/YRrrZhrxLr pic.twitter.com/koTDEex1Ed

— Meg Tirrell (@megtirrell) May 22, 2020

Premijerka Srbije Ana Brnabić izjavila je u Novom Sadu da je zdravstveni sistem Srbije doživeo ogromne pozitivne promene i da je zemlja zato spremno dočekala krizu izazvanu koronavirusom.

"Milijarda evra u zdravstvo je projekat koji je pokrenuo predsednik Srbije Aleksandar Vučić i taj projekat nam je pomogao da u ovoj krizi imamo najmanju smrtnost u Evropi i svetu"

rumbeando wrote:Oxford kaputt.

BREAKING: huge Chloroquine and Hydroxychloroquine study of 96,000 patients at 671 hospitals found:
Increased risk of DEATH by 33-45%
Increased risk of ventricular arrhythmia by 2.3x to 5x.
Not a trial but a large longitudinal study.
🧵#COVID19 https://t.co/SAD20nESOs pic.twitter.com/GPAulxCwNw

— Eric Feigl-Ding (@DrEricDing) May 22, 2020

A number of seroprevalence studies (that look for antibodies to covid and assess the overall level of population exposure) have now been completed in both U.S. and abroad, and they suggest that outside of epidemic cities; overal infection rates and exposure remain relatively low. pic.twitter.com/sHsueJyJFU

— Scott Gottlieb, MD (@ScottGottliebMD) May 21, 2020

Tegnell: We are doing two major investigations. We may have those results this week or a bit later in May. We know from modeling and some data we have already – these data are a little uncertain – that we probably had a transmission peak in Stockholm a couple of weeks ago, which means that we are probably hitting the peak of infections right about now. We think that up to 25% of people in Stockholm have been exposed to coronavirus and are possibly immune. A recent survey from one of our hospitals in Stockholm found that 27% of staff there are immune. We think that most of those are immune from transmission in society, not the workplace. We could reach herd immunity in Stockholm within a matter of weeks.

Sweden has revealed that despite adopting more relaxed measures to control coronavirus, only 7.3% of people in Stockholm had developed the antibodies needed to fight the disease by late April.
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Sweden's chief epidemiologist Anders Tegnell said the number was a "little lower" than expected "but not remarkably lower, maybe one or a couple of percent."
"It squares pretty well with the models we have," he added, while speaking at a news conference in Stockholm.

Why do some COVID-19 patients infect many others, whereas most don’t spread the virus at all?
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“If you can predict what circumstances are giving rise to these [superspreading] events, the math shows you can really, very quickly curtail the ability of the disease to spread,” says Jamie Lloyd-Smith of the University of California, Los Angeles, who has studied the spread of many pathogens. But superspreading events are ill-understood and difficult to study, and the findings can lead to heartbreak and fear of stigma in patients who touch them off.

Most of the discussion around the spread of SARS-CoV-2 has concentrated on the average number of new infections caused by each patient. Without social distancing, this reproduction number (R) is about three. But in real life, some people infect many others and others don’t spread the disease at all. In fact, the latter is the norm, Lloyd-Smith says: “The consistent pattern is that the most common number is zero. Most people do not transmit.”

That’s why in addition to R, scientists use a value called the dispersion factor (k), which describes how much a disease clusters. The lower k is, the more transmission comes from a small number of people. In a seminal 2005 Nature paper, Lloyd-Smith and co-authors estimated that SARS—in which superspreading played a major role—had a k of 0.16. The estimated k for MERS, which emerged in 2012, is about 0.25. In the flu pandemic of 1918, in contrast, the value was about one, indicating that clusters played less of a role.

Estimates of k for SARS-CoV-2 vary. In January, Julien Riou and Christian Althaus at the University of Bern simulated the epidemic in China for different combinations of R and k and compared the outcomes with what had actually taken place. They concluded that k for COVID-19 is somewhat higher than for SARS and MERS. That seems about right, says Gabriel Leung, a modeler at the University of Hong Kong. “I don’t think this is quite like SARS or MERS, where we observed very large superspreading clusters,” Leung says. “But we are certainly seeing a lot of concentrated clusters where a small proportion of people are responsible for a large proportion of infections.” But in a recent preprint, Adam Kucharski of LSHTM estimated that k for COVID-19 is as low as 0.1. “Probably about 10% of cases lead to 80% of the spread,” Kucharski says.

That could explain some puzzling aspects of this pandemic, including why the virus did not take off around the world sooner after it emerged in China, and why some very early cases elsewhere—such as one in France in late December 2019, reported on 3 May—apparently failed to ignite a wider outbreak. If k is really 0.1, then most chains of infection die out by themselves and SARS-CoV-2 needs to be introduced undetected into a new country at least four times to have an even chance of establishing itself, Kucharski says. If the Chinese epidemic was a big fire that sent sparks flying around the world, most of the sparks simply fizzled out.
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