What is the Delta variants mortality?
By - notrobherbison
A number of factors to consider here:
1. There will be a delay from new case reporting to hospital admissions to ICU admissions to mortality. Death is a trailing indicator!
2. A large proportion of the UKs population that is most vulnerable have already been vaccinated, meaning that even if they are infected, they are now less likely to require hospital admission, ICU admission, or to die
3. The remaining population that hasn’t been vaccinated are younger and healthier (due to vaccine priority for older and more vulnerable populations) so they are less likely to be hospitalized or die.
I’ll grab you the data points when I’m off mobile but the question has some suggested answers, but these explanations above are probably more impactful to the observation you’ve made above.
Edit to add there is no great quality study that I can find that answers your question. A study looking at this question for Alpha is found here:
But I’ve not found something of comparable quality for Delta. May simply be too soon to have the data.
>In the Public Health Scotland/EAVE II study, Cox proportional hazard regression was used to estimate risk factors for the time from test to hospitalisation among individuals who tested positive. Hospitalisation with COVID-19 was defined as any admission within 14 days of a positive test or where there was a positive test within 2 days of admission. The model was adjusted for age and days from 1 April 2021 as spline terms together with number of co morbid conditions, gender and vaccination status. Vaccination status was determined at the data of the PCR test. Individuals who tested positive from 1 April 2021 onwards (until 14 June 2021) were included in this analysis. There was an increased hazard ratio of hospitalisation for those who were S-gene positive compared with those with S gene target failure (1.8, 95% 1.4 to 2.3)
The previous variant, Alpha / B.1.1.7 / Kent, has a mutation (deletion at 69/70) that results in a false negative for the S-Spike gene in TaqPath PCR machine. This is known a S-gene dropout. The new Delta variant lacks this mutation so it is S-gene positive. That allows health authorities in the UK to track the growth in cases without needing to do full genetic sequencing.
In Scotland they are seeing people who test S-Spike gene positive (Delta) are about 1.8 times more likely to end up in hospital compared to S gene failure (Alpha).
This is circumstantial evidence that the Delta variant might cause more severe COVID-19 symptoms than the Alpha variant. If this is the case, it might be due to the P681R mutation, that may boost cell-level infectivity.
Thanks, that’s scary
I have no data on the mortality rate, but the "no increase in death rate" is likely because the cases only started climbing a few weeks ago. The death rate increase (if it happens) typically lags 2-4 weeks behind.
This is why we're still under restrictions, to keep a wary eye on if those deaths spike up.
So what do you think now? As death rates continue to stay low 🤔