Prof Irene Petersen
@i_petersen
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Professor of Epidemiology and Health Informatics
Joined January 2013
I wish anyone could please explain the logic of dragging a person who is infectious to a PCR test centre when they already know that they are infectious. Please @sajidjavid do stop this madness as soon as possible. .
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I will continue to wear a mask on public transport and in crowded places as long as more than 1 in 250 is infected in my local area (400 pr 100000).
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Whether you like it or not. It is our (hybrid) immunity that is ending the COVID pandemic ALL over the world.
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I *love* the logic of the COVID avoiders. First, they told us if we had maintained mask mandates omicron wouldn't have swept through the world. Now, that omicron has swept through the world, they suggest we reinstate mask mandates. Why?.
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It seems as there is a group of people who continue to believe that IF ONLY we wore masks or ventilated schools/public places then we would be able to 'control' the spread of an infectious disease like omicron. The reality is another. 1/.
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If @GeorgeMonbiot understood the basics of infectious disease epidemiology he would understand why it won't make a difference to keep children of school for a prolonged time. Likewise, he would understand that masking in hospitals DON'T work. 1/.
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There IS such thing as HYBRID immunity. New study from Denmark demonstrates . 3x vaxx + prior omicron infection -> 94% protection against BA.2 or BA.5 infection. 3x vaxx + delta -> 46% protection. 3x vaxx + alpha -> 65% protection . 1/.
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No, no, no! . Most of the world know by now that MASKS DON'T WORK. People like @trishgreenhalgh is driven by fear and have no understanding of basic infectious epidemiology.
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@michaelmina_lab @gayle In UK people can now leave isolation on day 7 following TWO negative rapid tests. To me that seems to be good use of rapid tests!.
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Feel free to continue to wear a mask or campaign for better ventilation but please do not pretend that it will have any major impact on the spread of COVID or that you are a better human than those who don't. 5/5.
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The mask fallacy: . 1."Lab studies shows masks work". 2. "I have worn a mask the last 2 1/2 year and therefore I haven't had COVID". 3. "If we all wear a good N95 mask we could reduce/prevent/end COVID". I often see these comments on twitter. Below I will discuss. 1/.
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This morning I had some fruitful conversations with two people who experience long covid. Based on these conversations I decided to delete my tweet about long convid users use of twitter. I acknowledge that the use of twitter may provide a lifeline for some people. 1/.
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How come @IndependentSage members are still talking about basic #COVID19 mitigations and transmission when most of the world have realised by now that: . 1) There IS NO SUCH THING as basic #COVID mitigation. 2) Measures of transmission reduction is irrelevant in the omicron era.
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It is getting more and more obvious. There is only one way out of this pandemic - HYBRID IMMUNITY. We can 'play around' with the viral world by changing our behaviours in different ways. Thus we can reduce the transmissions for a while, but the viruses come back to bite. 1/.
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Did you know that if you:. Test +ve on a LFT right now the likelihood that you are infectious is >99%. Even if you subsequently have negative PCR test the likelihood that you are infectious is STILL very high (>88%). 1/.
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Yes, there is a lot of Covid around. No, 'simple precautions' is not going to make a difference. There are things in life that are beyond human control whether we like it or not.
We are currently in a new wave of Covid-we can’t assume it’s gone away. Simple precautions and policy protections will go a help reduce harm for vulnerable and ease the NHS pressure. Comment by @chrischirp @SGriffin_Lab and me in this by @NicolaKSDavis .
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Up to now it made sense to slow COVID down and to reduce transmission to ensure most people got the best protection. Now it is time to change strategy. If we want to reduce serious illness and death from COVID we should seek to speed the epidemic up. 1/.
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Most people who have been following me for a while will know by now that I am a great fan of LFT (rapid antigen tests). The tests provide a quick answer and help people to navigate under difficult circumstances. Yet, it is time to evaluate the strengths and limitations.1/n.
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Yet another meaningless mask study with data from selected countries and time period. "Changes in COVID-19‒related daily mortality rate per million population from February 15 to May 31, 2020".
No big deal, just an 80% reduction in per capita covid death in countries that had mask policies. h/t @DickZoutman .
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From a population level perspective it doesn't make much sense to continue to wear masks to stop BA.2. It is so infectious that masks can no longer reduce transmission in a meaningful way. However, individuals may want to continue to wear masks for various reasons. 1/.
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Here is a man who is driven by fear rather than rational thinking. He doesn't understand the very basics of infectious disease epidemiology but it doesn't hold him back. .
Against a vast weight of evidence - of the great harms that Covid can do us, of the brevity of immunity, and of the rapid mutation of the virus - there are still some people pushing this dangerous nonsense. I dread to think how many people such advice might kill or disable.
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I understand why UK focus on getting those aged 50y+ COVID boosted this autumn. But. How come those aged under 50 can't buy a booster at a pharmacy if they want one? . (You can do that for the flu vaxx).
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@apsmunro @R_Hughes1 @ADC_BMJ From an epidemiological point of view masking children is probably one of the least effective ways to reduce COVID infections. The question is what made/make parents doing it? . My guess is it about psychology - the masks became a symbol of action. 1/.
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I don't know about you, but when people make statements like this without any supporting evidence I would call it scaremongering.
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Actually, you seem to have failed the empathy test by failing to understand that doing x,y and z don't make you a better person.
You could see Covid-19 as an empathy test. Who was prepared to suffer disruption and inconvenience for the sake of others, and who was not?.My column on the massive, ongoing, yet denied and minimised impacts of the virus.
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@piersmorgan Please consider those individuals who have had the vaccine, but are NOT protected sufficiently. By wearing a mask YOU may save their lives. Nobody may thank you, but do it anyway.
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They are fighting a fight that they will never win. .
China locks down part of Wuhan, nearly three years after first Covid case emerged
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Here is a thought. If you have a virus that has the potential to infect 5 other people (if they are susceptible) but it only infects about 1 (Rt ~1) then it suggests 4 out of 5 are immune. This is one of the reasons to why we don't see super spreader events anymore.
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Dear Americans, . Please don't fool yourself - you cannot stop COVID from going into schools by masking up your children. COVID will continue to spread as long as there are sufficient susceptible individuals around. 1/.
It's almost Back to School time & we're still seeing about 100k cases a day here in the US. How do we stop COVID from going back to school too? . Our new pre-print confirms face masks must be part of our plan!. Let me explain /🧵.
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I won't be signing this letter. I have fully supported use of face masks in secondary schools up to now. However, it is time to evaluate the benefits against the risks (see next tweets).
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When I see people tweets about. CO2 level on trains, theatre or other indoor venues.Giving up on indoor dining .being the only one with mask on . I am thinking it must be mentally exhausting. .
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The idea that we can make a COVID 'safe' society for people who are clinically vulnerable is a myth. Only YOUR immunity protects those who can't develop immunity themselves.
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Being double vaxed is making a difference to my life. I now *dare* to do things that I haven't done much for a very long time. It is great. And yes - I know the vaccine doesn't offer 100% protection.
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No!. This article is missing the most essential bit of information. As long as we don't know the difference in immunity from previous infections between the two communities the results are meaningless. The study tells us NOTHING about the effectiveness of masking in schools.
Brief thread on that "masks in schools" article in @nejm. It's a very well done article that I think many people have not actually read. 1/N
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How can @GeorgeMonbiot write columns for @guardian about COVID without knowing the most basics of infectious disease epidemiology?
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OK - now it is time for me to move on from COVID twitter. Thanks for sharing your thoughts and views - I have learned a lot!.
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"No evidence" schools spread lots of coronavirus, UK researchers say
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The head of the COVID scaremongering society @1goodtern doesn't like it when his fellow scaremongers are being encouraged to move on.
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@SaskiaPopescu Thanks for sharing, this is a great example of why masking isn't going to prevent COVID infections. Every time you are exposed to an infectious person there is a risk that you will get infected. Let say that risk is 1/10 without mask and 1/20 with a mask. 1/.
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There are many thing about #COVID19 that is absurd. For example, I am wondering how come a group of very clever academics in UK have come to the conclusion that quarantine of children and young people is ETHICAL and/or EFFECTIVE if alternative options are available?.
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Last week we published a paper illustrating that lateral flow tests are much more accurate than many previously thought. How come??.1/n.
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In the last few days we have seen a lot of shouting on twitter about the pilot music events in Liverpool. Scientists and health researchers have been up in arms. In my view it is time to CALM DOWN and support this work.
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The head of the COVID scaremongering society @1goodtern really really doesn't like it when his fellow scaremongers are being encouraged to move on.
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It is interesting to note how some people draw up conclusions about why they haven't had COVID yet. Many people fail to realise that they are now protected by other peoples immunity.
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Likewise, @GeorgeMonbiot should be aware by now that there is NO such thing as 'covid safe environments'. Most people will get infected several times in their life whether they wear a mask or not. He is fighting a fight he can't win. 4/4.
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Whether we like it or not, it IS our immunity that is doing the heavy lifting. Thus, in the past few weeks there have been several studies demonstrating that individuals who have been 3x vaxx and previously infected are MUCH better protected against BA.5. 2/.
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@Embyeye @GeorgeMonbiot You should go and hide under a rock for the rest of your life. Alternatively, you should accept that if you want to live an active life you are likely to catch COVID several times.
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You seem to be 'drowning' in the waves and miss very important elements of infectious disease epidemiology. People DO develop some immunity over time - we don't start at square one each time.
THREAD on why "living with" frequent mass Covid infections is a BAD IDEA (& what we can do!): . There is a negative feedback cycle for transmission & *each time* we go through it in a wave we damage our people, our NHS and our economy a bit more. let me show you how. 1/17
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@KashPrime If they knew something about infectious disease epidemiology they would know that masks are unlikely to make much difference when it comes to the risk of getting COVID.
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It takes time to come to terms with the fact that infectious diseases like COVID are primarily controlled by the level of immunity in the community. As humans we can try to delay transmission for a little while but people will still get infected if they are susceptible. 2/.
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This letter contains so many errors that I gave up counting. However, let's look at why mask mandates in health care settings are unlikely to have any major impact on COVID infections. 1/.
Send this letter to your local healthcare providers to encourage better protection of staff and patients from COVID-19.
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This is a reminder that you should be cautious when you see people considering themselves 'experts on masking in schools'. This guy (yes it is a guy) base his 'expertise' on anecdotes and nothing else.
@i_petersen This is your occasional reminder that I am an expert on masking in schools, and that Irene has not bothered to investigate this area.
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So I got a question. How come masks did work in the delta era but not in the omicron era. I thought about it and then I realised actually it wasn't the masks but the vaccines that did the hard work. Then omicron came along and now it is the hybrid immunity doing the work.
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Lateral flow tests may be more than 90% effective at detecting people at their most infectious, study finds
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This is a very important read for anyone who are considering reimposing mask mandates in schools.
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I am yet to see a study that demonstrates masks mandates in schools reduce COVID infection among school children in 2022. (Temporarily transmission reduction in a specific setting is irrelevant).
The evidence on the efficacy of masks in reducing school transmission really is overwhelming now. We cited many studies - there have probably been more since!. Ditto on less long lasting antibody protection in kids after infection. 4/8
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I am NOT against. Use of FPP2 masks .Ventilation.Increased vaccine uptake among young people . but I am NOT convinced that any of the interventions have any major impact on the future of COVID infections in UK.
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So can we use rapid tests as 'green light' tests in the omicron era? . Perhaps, if we are aware that a -ve result expires very quickly . and. therefore we need to take the test JUST before meeting up with other people (or on the doorstep). A test from yesterday is not enough. 5/n.
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A short but sharp wave reduces the time where the prevalence of COVID is high and thus the risk of infections is high. We might be able to alter the shape of the waves with NPI but if we don't change the overall duration we haven't gained much. 4/.
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Then people say what about the vulnerable who can't 'afford' to be infected? . The truth is that the only way we protect the vulnerable is to build a wall of immunity around them and that we build that wall sooner rather than later. In other words . 3/.
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It really is time that we dare to stand up and say it LOUD. Non-pharmaceutical interventions (NPI) were needed to manage the size of the pandemic early on. They were needed to protect our health care systems before we got 3x vaxxed. BUT NPI isn't the way forward. 3/.
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Therefore, if @GeorgeMonbiot was serious about protecting vulnerable people he should promote children in schools getting infection acquired immunity sooner rather than later during any outbreaks. 3/.
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Here is a short thread about the probability of getting at least one 6 if you role a die 20 times. The probability is 1/6 if you role it one time. If you role it 3 times it is .1 - (5/6) x (5/6) x (5/6) = 1 - 91/216 = 42.13%. 1/
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This leads to the final question. Would it be possible to significantly reduce COVID at community level by mask mandates? . My view is NO, and here I will try explain why. (You are welcome to disagree as long as you do it in a respectful way :-)). 6/.
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There are still people who are stuck in the pre-omicron era - @TRyanGregory seen to be one of them. .
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@yaneerbaryam Just a reminder of what a 'dynamic zero strategy' looks like: .
Day 47 of our Shanghai Covid lockdown and we woke up, like we often do, to a man in a hazmat suit downstairs yelling through a bull horn for us to come down for our tests. While checking our phones for the new test QR code, we also saw this alarming new official notice sent to us
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Wonder how many studies like this need to be published before it becomes clear that the 'clean air' slogan/campaign is nothing more than empty words designed to make people feel better.
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If I remember correctly, it was about now all the scaremongers predicted that there would be major outbreaks of covid because of BA.2.86. So why didn't it happen - probably because most of us now have some level of immunity and hence we no longer end up in hospital. .
Still a fast decline in England, despite BA.2.86 + JN.1 making up ~30% of infections in the most recent timeframe.
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If you want to read one thread about COVID today - this should be the one! . It is excellent!.
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Let me guess. We will soon see numbers of BA.2 cases fall in most of UK. Why? . We have reached a high level of immunity from vaccines + infections. Areas with low level of previous infections may take a bit longer.
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@DrDavidRSewell All current tests would have been approved before #omicron. However, it appears that in some cases, omicron infect your throat before your nose. If you take a throat swab as well as nose swab, please do not eat 30 minutes before as the tests may be sensitive to acid.
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Some studies have shown a reduction in transmission due to masks others have not. I am yet to see a really strong well designed study that demonstrates a large reduction in transmission at community level due to masks. 5/.
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@taipan168 Yes, it seems as if there are still some people who: . 1. Struggle to come to terms with the fact that COVID will continue to be around. 2. Has a blind faith in masks/clean air will protect. 3. Exaggerate the prevalence of potential adverse outcomes.1/.
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@EpiEllie Me an epidemiologist: both research and real life shows widespread mask use does NOT reduce respiratory infections.
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I just want to take my hat off for @jillahjillah for letting @dgurdasani1 know that she has got the wrong end of the stick. Of course @dgurdasani1.didn't like to hear that but it comes as no surprise.
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Sometimes you wonder what the pandemic has done to people. I hope for @psvbluemts that he will be able to leave his CO2 monitor at home next time he goes to a live event.
Last night I attended my first live theatre event since the pandemic. This is the CO2 plot for the evening (the level in the foyer during interval was fine). The recommended max CO2 under the NCC is 850ppm This state of the art 2400 seat theatre opened in 2019.
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It doesn't mean that there aren't individuals and sub populations who can benefit from the use of masks and/or regular testing e.g. people in hospitals or care homes. but as society we are only going to get to the end of the pandemic via HYBRID IMMUNITY. 4/4.
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It is important that we begin to understand and prepare ourself on getting our social life back in the post-pandemic era. Hopefully @dgurdasani1 will soon realise that it would be irresponsible and unethical NOT to do pilot studies.
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What is the worst analogy for mask protection you have come across? . Condoms.Seatbelts.?.?.
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👨🦰: I didn't read the study but if 👨🦳 retweeted it then it would be good enough to me. 👨🦳I didn't read the study but 👩🦰is famous so that would be good enough to me. To cut a long story short: . The study ISN'T GOOD enough - please don't retweet a study that you haven't read!.
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@HelenRSalisbury @EricTopol Please note we cannot stop omicron spreading. If you want to make a difference please use your platform to encourage people who have 2x vaxx to get their 3rd jab. That will save lives.
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Just a short note to say THANK YOU to the millions of people around the world who spent a few minutes to take rapid test (LFT) before meeting up with families and friends this Christmas.
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Third, the sensitivity is also high. Which means if you get a -ve results it is likely that you are NOT infectious AT THE TIME you take the test. BUT, BUT you should be aware that you may switch from being noninfectious to infectious within hours. 3/n.
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I have noted there are some people who have a tantrum on twitter, often because they don't like what they have just read. Then they write a lot of ugly words. I wonder if it makes them feel better?.
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If I was editor at @bmj_latest I would invite the authors of this response to write a full paper on Covid-19 in Europe; policy on children and schools.
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@Ninawildflower The likelihood that your son is going to get infected whether he wears a mask or not is very high if he is susceptible. Perhaps it is time for you to accept this?.
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Important thread about release from isolation. IN SHORT:.If you are boosted you may develop symptoms early and isolate early. Therefore likely to STILL be infectious on day 5. Please use rapid tests before going back to work.
1/ @CDCgov exit isolation at day 5 w/out Neg Rapid Ag Test = dangerous policy. Important New Research. We followed 260 Health Care Workers returning to work early. • ~58% Pos on Day 6 (72% if Boosted!).• 50% w high virus load.• **Positivity 2x-3x HIGHER if Boosted**. A thread
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@PeteUK7 Perhaps worth checking out the latest numbers and trends on the COVID dashboard before engaging in your next 'educational' dialog.
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@CattonKelly Omicron will rip whatever we do - the question is now about the timing. Do we let it rip when most people are protected either by 3x vaxx or recent infection or do we delay and fewer people will be protected.
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It may also be correct that some people have been able to avoid getting COVID up to now by wearing a mask. (i.e. if they hadn't worn a mask they would have had COVID). However, there are also people who haven't worn a mask who have been able to avoid COVID. (Anecdotal data). 3/.
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@carlheneghan Sensible people would take a test on regular basis and STAY HOME if they are INFECTIOUS. and a sensible government would PAY people to STAY HOME if they are INFECTIOUS.
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I find it pretty amazing to watch how the infection aquired immunity holds up among children and young people in UK in the autumn 2022 despite new variants and no 'mittigations'. This suggests that UK made the right decision to focus autumn boosters on 50y+.
Up to 2022, kids had highest infection rates in every wave, esp secondary school in autumn 2021 (remember late vax roll out?!). First half of 2022 saw mass infections in primary school kids (also late 5-11 vax rollout). But Oct & Dec 2022 waves were driven by adults. 3/13
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However, I still see a merit in masks for individuals who are at high risk if they catch covid and in specific settings f.x. hospitals. 11/11.
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Why don't be honest a say that you are wearing a mask because you believe it may reduce YOUR risk of getting COVID. And then accept others may or may not wear a mask for other reasons. F.x. millions have recently recovered from COVID and hence they are very low risk to you.
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It amazes me how much power I (and people like me) have.
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In short, we are on the way to reach 95%+ immunity - let's get there before the vaccines wane. 6/6.
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