- and Nicola Surgeon of course. Clinical and immunological assessments of asymptomatic SARS-CoV-2 infections. In mildly symptomatic and asymptomatic patients, a lower proportion seroconvert (Long et al, 2020). Specifically, careful examination of the weekly all-causes mortality data in France is completely clear. The UK has suffered approximately 42,000 such deaths which, to a first approximation using IFR, implies 16.8million infections, or 25% of the population having been infected. There is no biological principle that leads us to expect a second wave based on the accumulation of data over the past six months. A modification to the strategy involving PCR testing which would easily resolve any uncertainty is this: every positive test result is followed up as quickly as possible, ideally within 24 hours of the positive result, and every one is retested. A second wave hasnât happened yet, but that doesnât mean those who predicted one have been proven wrong. For a second wave to start you would need a sustained rise in infections. The COVID-19 pandemic has undoubtedly allowed for some very positive and rapid changes within NHS pathways, protocols and services which should be maintained. Ling, et al (2020). It has widely been observed that in all heavily infected countries in Europe and several of the US states likewise, that the shape of the daily deaths vs. time curves is similar to ours in the UK. This is because the antibody system is but one of several tools our immunology has to defend us. They are working with manufacturers to stock up on equipment, and they are continuing their policies for protecting patients and staff members. Enforcement of this policy is at the discretion of this websites administrators. They are distinct from the others in the population who do not have these T-cell responses and are therefore susceptible to a new virus. But even here, it is important to recall what it is that the PCR test measures, and it is simply the presence of partial RNA sequences present in the intact virus. Interestingly, this question of what percentage of the population have been infected can be approached using a different methodology. The Gompertz-type plot seen above, which is formed by a single surge in activity, often followed by smaller minor upturns as the disease reaches new populations, is typical of previous virus outbreaks that have been well documented, none of which have demonstrated a significant second wave even though control methods were used to prevent the spread of disease in each case. Daily deaths from and with COVID-19 have almost ceased, having fallen over 99% from peak. Epidemic outbreaks A recent letter to the British Medical Journal (Healy, 2020) exemplifies the extent of harm that actually arose in a setting in which all but one of the positives ended up being false positives. Let us take a midpoint value, especially as for months the US CDC displayed a value for IFR of 0.26% on their website. Obviously, and perhaps it has already happened, there is the potential for emerging influenza to complicate the picture. This means that even a true positive does not necessarily indicate the presence of viable virus. The impact of host resistance on cumulative mortality and the threshold of herd immunity for SARS-CoV-2. This is the basis of all the second wave fears we hear about. Prior to this, three other groups including immunologists in Germany, Sweden and the USA each independently published similar findings (refs as above and discussed in Sewell, 2020). Since June 26th the number of weekly deaths has now fallen so it is not only below the weekly average but has regularly dropped below the lower control limit, showing that we are now at the lowest number of weekly deaths recorded in many years. Nothing is too small. The problem of using any assay to conduct surveillance on a low prevalence virus with a PCR test has been widely discussed (Heneghan, 2020). Instead, it is likely there will be local, small and self-limiting mini-outbreaks as areas previously unexposed come into contact with the virus. It had previously been suggested that pre-pandemic immune responses in circulating T-cells might have occurred following exposure to one or more of the endemic coronaviruses. Current mass testing using ⦠These cohorts represent approximately 11.9% and 19% of the UK population, respectively. This means that even a true positive does not necessarily indicate the presence of viable virus. Science. Ct values above 30 returned negative cultures in all except one case. Mateus, by using parts of these endemic coronaviruses which also exist within COVID-19 confirmed this. There are approximately eight million children aged 0-10 in the UK and 12.7 million aged 0-15. https://www.cebm.net/covid-19/global-covid-19-case-fatality-rates/, ONS coronavirus survey (Aug 14 2020). (2020). September 28, 2020 The officials in Sweden appear to be of the view that their population has closely approached or in some places reached what they term herd immunity, with R persistently lower than 1. Understanding the age divide in COVID-19: why are children overwhelmingly spared? The past four years data were used for comparison purposes and to calculate upper and lower control limits (based on two standard deviations). This has occurred because the level of infection required to introduce enough immunity into the population to reduce the reproduction number (R) permanently below 1 occurred at markedly lower infection rates and loss of life than had been initially anticipated. Instead, it is likely there will be local, small and self-limiting mini-outbreaks as areas previously unexposed come into contact with the virus. Chief Science Officer for Pfizer Says “Second Wave” Faked on False-Positive COVID Tests, “Pandemic Is Over. Current evidence allows for a greatly improved understanding of positive infectious patients; and using the evidence to improve measurements and understanding can lead to sensitive measurements of active cases to give a more accurate warning of escalating cases and potential issues and outbreaks. COVID-19 is new, but coronaviruses are not. Restrictions have been progressively eased across the country for over three months. Under present parameters, even accepting an unlikely 0.1% False Positive rate and a prevalence of 0.1%, more than half of the positives are likely to be false, potentially all of them. Current evidence allows for a greatly improved understanding of positive infectious patients and using the evidence to improve measurements and understanding can lead to sensitive measurements of active cases to give a more accurate warning of escalating cases and potential issues and outbreaks. Gallais, (2020). The Spectator, July 20 2020. Finland: The Covid Success Story No-One is Talking About. This is a conservative value since current literature finds that between 20% and 50% of the population display this pre-pandemic T-cell responsiveness, meaning we could adopt an initially susceptible population value from 80% to 50%. Change in this parameter is likely to be a much more sensitive measure of the presence of increasing prevalence of SARS-CoV-2 infection than flawed PCR testing without modifications. Did COVID-19 infections decline before UK lockdown? It is recommended that a greater focus be placed on evidence-based medicine rather than highly sensitive theoretical modelling based on assumptions and unknowns. Gallais (2020) shows that none of the familial contacts of those testing positive to SARS-CoV-2 went onto to develop antibodies. This resulted not only in considerable time and money wasted by surgeries, but also other medical issues being delayed. MedRxIV https://doi.org/10.1101/2020.07.15.20154294, Mateus et al (2020) Selective and cross-reactive SARS-CoV-2 T cell epitopes in unexposed humans. Six weeks into an apparent surge of cases, the number of deaths remain completely flat and normal, in all age bands (as of mid-August when this document was written). That would have resulted in very many more deaths than have been measured. But if, as we are now reasonably sure, a much lower initial percentage was susceptible, it takes far fewer people to catch the virus before there are too few susceptible people remaining within the population for the virus to be able to find the next person to infect. Over the last three months since lockdown measures started easing on the May 10th there has been no increase in weekly deaths. Based upon guidance from NHS England, our primary and secondary care service across the country are currently following protocols to limit access to care due to the dangers of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or COVID-19) pandemic. It’d be a poor immune system which lets that happen, and we’d probably not have made it as a species into the 21st century if that’s how it worked. Infection , Genetics and Evolution. If it is to continue, then results and reporting should be refined to meet the gold standard of testing methodology to give clinicians improved information so that they are able to make appropriate clinical decisions. Covid-19 testing, low prevalence and the impact of false positives. (2020) Genomewide Association Study of Severe Covid-19 with Respiratory Failure. This is a conservative value since current literature finds that between 20% and 50% of the population display this pre-pandemic T-cell responsiveness, meaning we could adopt an initially susceptible population value from 80% to 50%. Sekine et al. We have now seen this in a number of nations, in a small number quite dramatically. CapeTalk's Africa Melane poses the question to Professor Alex van den Heever, from the Wits School Of Governance. https://arxiv.org/pdf/2005.02090.pdf, Gniazdowski V, Morris P, Wohl S et al. New Eng. Obviously, and perhaps it has already happened, there is the potential for emerging influenza to complicate the picture. What Connection Does Gibraltarâs High Covid Death Rate Have With the Vaccines, if Any? Sweden Did in Fact Lock Down When it Came to Care Homes. In a study of 23 people who survived SARS in 2003, every single one had memory T-cells that recognised the SARS virus 17 years later (Le Bert et al, 2020). This means that a factor of two-fold and possibly higher would need to be applied to population serology data in order to better approximate the infected population. Instead, it is likely there will be local, small and self-limiting mini-outbreaks as areas previously They now recommend not testing people with no symptoms who are not contacts in a contact-tracing activity. Clinical and immunological assessments of asymptomatic SARS-CoV-2 infections. This is crucial to understanding where we are with respect to the epidemic in the UK and the potential for a second wave of infections. The evidence we’ve presented leads us to believe there is unlikely to be a second wave, and that while there have been apparent multi-‘wave’ respiratory viruses in the past, notably 1918-20, in many cases it became clear that this was either different populations being infected at different times or in some cases multiple different organisms involved. They all have striking sequence similarity to the new coronavirus. The virus infection has passed through the bulk of the population as a result of wholly natural processes and evidence indicates that in the UK and other heavily infected European countries the spread of the virus has been all but halted by a substantial reduction in the susceptible population. We do not know exactly what the false positive rate is, but it is widely believed to be greater than the actual, remaining prevalence of the virus (Heneghan, 2020), which is around 1:2000, or 0.05%. Dale Shamp says: September 29, 2020 at 8:06 am I have finally started to realize, after talking to my daughter, that this Covid thing is just a big money maker. The COVID-19 pandemic has undoubtedly allowed for some very positive and rapid changes within NHS pathways, protocols and services which should be maintained. “Is it flu or is it COVID-19?” is a question easily answered. The key point about ‘cold positives’ is that they are not ill, not symptomatic, not going to become symptomatic and, furthermore, are unable to infect others. Immunity threshold Numerous estimates have been made of the infection fatality ratio (IFR) for this new virus. Instead, it is likely there will be local, small and self-limiting mini-outbreaks as areas previously unexposed come into contact with the virus.
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