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on Delhi's COVID epidemic - to put the devastating current news in context. The desperate hunt of beds, the shortages of oxygen, almost 30K positive tests and over 250 recorded deaths in one day, every third person tested found positive. https://timesofindia.indiatimes.com/city/delhi/delhi-records-28395-new-covid-19-cases-277-deaths-amid-desperate-hunt-for-beds/articleshow/82164244.cms
on Delhi's COVID epidemic - to put the devastating current news in context. The desperate hunt of beds, the shortages of oxygen, almost 30K positive tests and over 250 recorded deaths in one day, every third person tested found positive. https://timesofindia.indiatimes.com/city/delhi/delhi-records-28395-new-covid-19-cases-277-deaths-amid-desperate-hunt-for-beds/articleshow/82164244.cms
This is Delhi's *fourth* COVID surge. It's overshadowing all the others. As in other cities this tragedy comes when so many have already been infected. By Jan 2021, >50% of the city had been infected. This estimate is backed up by lots of data and analysis (refs at the end).
Prior to this wave, things seemed under control. By mid-Feb, with 60K daily tests Delhi was finding only 100-150 cases. There were 1 or 2 daily deaths. This is unlike Mumbai which was testing much less but reporting more infections & deaths even in the "calm period".
The rise of this wave in Delhi was slow at first. R actually crossed 1 in mid-Feb, but hovered below 1.5 until March 19 by which time there were about 700 daily cases. Since April 5 it has been ~2. Deaths started a clear rise around March 19, and recently shot up.
My latest estimates (last year): about 1 in 10 infections were being picked up in testing. In the last week there have been ~1.5 lakh cases - at 10% detection this would correspond to 1.5 million new infections (8% of the city). The reality is almost certainly worse...
...Delhi has always tested a lot (unlike Mumbai). But once you get the kind of test positivity you see now, it means detection has gone down. So it seems likely that in the last week more than 10% of the city got infected. Shocking.
This is all particularly unbelievable given that more than half the city has already been infected. This brings us back to the question of what variants might be circulating in Delhi. Unfortunately I can't find any data on this. (Others will know more.)
But, we have to assume that whatever is circulating in Delhi is either extremely transmissible or fairly easily able to infect people who have previously been infected. In fact, with R ~ 2, it's hard to believe increased transmissibility is enough to explain the surge.
It is hard to know just how deadly this wave will be. Delhi's fatality rate - in terms of recorded deaths - has been quite a lot lower than Mumbai's, but it rose in the second half of 2020. Perhaps disease was moving more in older populations. https://scroll.in/article/978548/why-is-covid-19-surging-in-delhi-eight-months-after-the-pandemic-started
The current signs are that this wave is going to see a high fatality rate. Even if deaths are only lagging one week behind cases, daily deaths could double and cross 500 a day. A rapidly unfolding tragedy unfolding in the city.
References. Many estimates from last year in this technical document including a median prior infection of 50% in the city in Oct. 2020.
http://maths.mdx.ac.uk/research/modelling-the-covid-19-pandemic/delhiwaningantibodiesnotes/
This estimate was confirmed by a serosurvey in Jan which found 56% seroprevalence. (n/n) https://www.hindustantimes.com/cities/delhi-news/delhis-5th-sero-survey-over-56-people-have-antibodies-against-covid19-101612264534349.html
http://maths.mdx.ac.uk/research/modelling-the-covid-19-pandemic/delhiwaningantibodiesnotes/
This estimate was confirmed by a serosurvey in Jan which found 56% seroprevalence. (n/n) https://www.hindustantimes.com/cities/delhi-news/delhis-5th-sero-survey-over-56-people-have-antibodies-against-covid19-101612264534349.html
