Thu Dec 30th, 2021 at 03:01:07 PM EST
Vaccination Effectiveness Omicron #gauteng SA
Two doses of Pfizer #COVID19 vaccine are 50-70% effective against hospitalization caused by variant #omicron
Excellent review of status Covid-19 infection and hospitalization in South Africa - #gauteng.
Does omicron cause less serious disease than delta and will omicron waves be shorter in duration than delta waves?
South African and UK hospitalisation data: What it tells us about how deadly omicron is
Recent official South African medical reports and countrywide novel coronavirus disease (COVID-19) data have indicated that since early November, when omicron was first detected, COVID-19 cases substantially increased. However, most patients had, at worst, mild symptoms, and cases are now in steep decline. These observations substantially differ from the previous waves, including those attributed to the delta variant.
Reporters also stated that even though vaccinated and unvaccinated people developed the disease in roughly equal numbers, most hospitalised patients were unvaccinated. And although the current South African COVID-19 wave may be coming to an end, South Africa's omicron wave experiences may follow very similar patterns in other countries.
In contrast to this relatively encouraging news, some recent tweets and localised reports suggest that some hospitals in South Africa have experienced - or are experiencing - increasing numbers of hospitalised patients, with increasing numbers of patients requiring treatment in intensive care units and needing mechanical ventilation - a key indicator of severe COVID-19.
A review of official South African COVID-19 countrywide figures from 1 Dec. 2021 to 21 Dec. 2021 shows new confirmed COVID-19 cases per million population rose dramatically from 63 to 303 (a 380% increase), while total deaths only rose from 0.466 to 0.583, (a 25% increase). At the same time, the rate at which all COVID-19 infections were estimated to spread (the R rate) steadily decreased to around 54% of the Dec. 1 value.
PS Just as now seen in The Netherlands, the severity of number of cases is on par with previous waves of patients on ventilators. The duration of normal treatment in a hospital is much less.
Rapid tests do not perform sufficiently reliable for the Omicron variant ...
Omicron Variant: Impact on Antigen Diagnostic Tests
Temporal dynamics in viral shedding and transmissibility of COVID-19 | Nature Medicine - updated Aug. 2020 |
We report temporal patterns of viral shedding in 94 patients with laboratory-confirmed COVID-19 and modeled COVID-19 infectiousness profiles from a separate sample of 77 infector-infectee transmission pairs. We observed the highest viral load in throat swabs at the time of symptom onset, and inferred that infectiousness peaked on or before symptom onset. We estimated that 44% (95% confidence interval, 30-57%) of secondary cases were infected during the index cases' presymptomatic stage, in settings with substantial household clustering, active case finding and quarantine outside the home. Disease control measures should be adjusted to account for probable substantial presymptomatic transmission.
Quantifying the relationship between SARS-CoV-2 viral load and infectiousness | eLive - 2021 |
After more than 18 months of an unprecedented pandemic, some key aspects of virus transmission remain poorly understood. While respiratory droplets and aerosols have rapidly been demonstrated as a major route of transmission of SARS-CoV-2 (Tang et al., 2020), the role of the viral load as a driver of infectiousness has been established (He et al., 2020) but not quantified. This lack of evidence is due to the fact that high-risk contacts occur mostly before the index has been diagnosed, with no information on the viral load level at the time of the contact. The relationship between viral load and infectiousness determines the timing of transmission, the inter-individual heterogeneity in transmission, and ultimately the impact of interventions (contact, case isolation, vaccination) on transmission. In the context of variants of concern, that are associated with larger viral loads (Teyssou et al., 2021; Liu et al., 2021; Elie et al., 2021; Cosentino et al., 2021; Jones et al., 2021), it becomes even more critical to delineate the contribution of viral load from other factors associated with an increased transmission. Further, as antiviral drugs and vaccine strategies are being implemented, that dramatically reduce the amount of viral shedding (Levine-Tiefenbrun et al., 2021), it is essential to understand how they may contribute to a reduction in virus transmission.
One of the most documented clinical study to address the question of viral load and infectiousness has been obtained through individuals included in a randomised controlled trial conducted in March-April 2020 in Spain, that aimed to assess the efficacy of hydroxychloroquine on SARS-CoV-2 transmission (Mitjà et al., 2021; Marks et al., 2021). Overall, 282 index and their 753 high-risk contacts were frequently monitored to assess their virological and clinical evolution. An association was found between the probability of being infected after a high-risk contact and the viral load measured at the time of diagnosis in the index case (Marks et al., 2021). This suggests that viral load is associated with transmission; however, it does not quantify the role of viral load in disease transmission, as the viral load at the exact time of the contact remains unknown and may greatly differ from that measured, several days later, at the time of diagnosis.
Understanding the drivers of transmission of SARS-CoV-2 | The Lancet - Feb. 2, 2021 |
Marks and colleagues found that the viral load of the index case was strongly associated with the risk of onward transmission (adjusted odds ratio per log10 increase in viral load 1·3, 95% CI 1·1-1·6) and that this risk was higher for household contacts (2·7, 1·4-5·06) than for other types of contact (health-care worker, nursing home worker, or nursing home resident). Additionally, they found a small, but significant, effect for age of the contact person, with older individuals being more at risk of becoming infected. Because the included population of both index cases and contacts consisted mainly of adults aged 27-57 years, more important age effects, such as those for children, might have been difficult to identify.
We can't vaccinate our way out of the Covid-19 pandemic
Let'r fly as in herd immunization clearly makes the pandemic worse for the population and business ...
The UK and Boris Johnson is following the Trump era "science" of feel good ...
Boris and the wrecking ball to destroy healthcare and the NHS ... when politics gets in the way of personal well-being, health and medical advice.
Taking the words of Donald Rumsfeld ... last throes of Boris
Last jump to safety by Boris ...
Dad's Army ...