R-Value and it's Covid Travails

SARS-Cov-2 aka Covid-19, the virus behind the current pandemic continues to be a nightmare for everybody - especially for statisticians. 

It was bad enough to have the Chinese obfuscating the truth about the original 'Wuhan virus' last year, but now we have a range of mutants (and double-mutants) that seem to be spreading in ways that are difficult to predict. This is is making the work of those who prepare statistical models much more difficult, and this in turn is affecting the quality of decisions being taken by policymakers.

Take for instance, the reproductive-value or R-Value for Covid-19. R is the number of people that one infected person will pass on a virus. 

The lowest possible R-Value is R-naught or R0. Also referred to as the Basic Reproduction Number, it is the R-value of a population that is assumed to have zero immunity against a new infection. R0 is the division of the number of new infections by the number of existing infections, or the average number of new infections over an infectious period (R0= new infections/existing infections).

Measles has an R number of 15 in populations without immunity. It means that, on average, every 10 people with Measles will infect 15 other people. For Covid-19, the latest R-value estimate for India, is around 1.30. This number is showing wide variations across states with Uttar Pradesh recording the highest infection value at 1.62, followed by Andhra Pradesh at 1.61.

The problem with the R-Value is that it gives us a picture of the past - by the time you calculate it, the number is already outdated. This is because it is based on data recorded on hospitalisations and death figures to get a sense of how many people have the virus – but the problem with this is that, since the virus’s incubation period is so long, it only gives an accurate picture of a few weeks ago.

Add to this the complications coming from recent mutations of the virus in different parts of the world, each with its own incubation period - the "UK" B.1.1.7; the "South Africa" B.1.351; "Brazil" P1, "India" variants B.1.36 (Bangalore) / B.1.1.7 (Punjab) and B.1.617 which contains two specific mutations - E484Q and L452R which is capable of 'immune escape', and infecting those who have already been vaccinated. 

Add to all this other newer emerging variants of concern (VoCs) and we have all ingredients for a statisticians' perfect nightmare. 

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LINKS & REFERENCES

* https://www.bbc.com/news/health-52473523

* https://theprint.in/health/indias-covid-r-value-increases-to-1-30-this-week-the-highest-since-april-2020/633783/

* https://www.weforum.org/agenda/2020/05/covid-19-what-is-the-r-number/

* https://www.statista.com/statistics/1101713/india-covid-19-cases-by-type/

* R0 Explained - https://indianexpress.com/article/explained/coronavirus-r0-reproduction-number-explained-6354339/

Covid Shielded

The lady who helps us with the housework is from a remote coastal village in West Bengal. Yesterday she got a call from her parents and the news was that they were both suffering from fever. A few thousand kilometres away, near the capital city, we too were afflicted by the same symptoms - the expected after-effects of a vaccination national drive against Covid-19. 

We were among the four million+ people who got vaccinated in India today. While the fever and the dull pain of an intramuscular injection abates, it is quite amazing to think of superlative effort that has gone into creating, testing and delivering these vaccines all over the world.

The vaccination program started its rollout in India couple of months ago. First for those over 65 years of age, and for those who were vulnerable due to 'co-morbidities'. At first people were wary, and senior citizens had to be coaxed and cajoled to the vaccination centres. This changed on 1 April 2021 when the government decided to expand the coverage to those over 45 years of age.

The sheer scale of this effort does not hit you until you participate in it. It is a four step process is driven by information technology in which each dose can be traced back to a specific vial at a specific vaccination centre:

(1) Registration at CoWIN site - a single phone can be used to make four bookings at either government 

(2) Selecting a vaccination centre - Based on your postal PIN code you can opt for either the nearest government centres (free of charge) or private hospitals / clinics (fixed at INR 250) 

(3) Vaccination - At the hospitals a queuing system ensures that people maintain social distance. Each vaccine station has three staff  - two for writing out the registration details, one  for preparing the vaccination card, one for checking the CoWIN id, uploading the confirmations online, and a nurse who administers the vaccine. The whole process takes about 8 minutes. After the jabs people are expected to wait for 30 minutes of observation before returning home. 

(4) Certificate - within a few minutes of getting vaccinated an SMS message leads you to an online certificate (PDF) which can be used as proof while travelling.

(4) Follow-up - each vaccinated person is given a card which specifies the vaccine type (Covidshield / Covaxin), the date for the second dose (min. 28 days), emergency helpline numbers and a list of five possible after effects (mild fever, pain and swelling, etc.,)

One thing I have learnt along the way is that the government machinery seems to be far more efficient than the private sector. In my immediate neighbourhood all the hospitals were booked until 14 April, so I expanded the generic Noida PIN code and booked two slots on 1 April at Metro Hospital from a list of about 10 hospitals. 

However my experience at Metro Hospital left me quite disappointed. It is a large hospital in Sector-11 Noida. When I found my way to the entrance the staff seemed paralysed by chaos - there were over a 100 angry, impatient people already crowding inside, with the guards telling the newcomers that they would need to wait for three hours!

I went back to the CoWIN site and got my appointment rescheduled to the  next day at the District Combined Hospital, a government facility in Sector 30. Over here the whole process was a breeze. There was ample parking outside; masks, hand sanitisers and social distancing was compulsory; tokens were being distributed at the main gate and security guards were systematically guiding people through waiting halls while giving priority to the elderly and infirm.

Millions of tiny vials from Oxford-AstraZeneca / Serum Institute of India, Sputnik and J&J have now set out to deal with a virus from China that had the world paralysed for more than a year. Hope is in the air, and in our blood streams.

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LINKS & REFERENCES:

https://www.livemint.com/news/india/covid19-vaccination-over-36-lakh-people-get-the-jab-on-april-1-the-highest-so-far-11617335903675.html

https://www.bbc.com/news/world-asia-india-55748124 - Covishield and Covaxin: What we know about India's Covid-19 vaccines

On the remarkable role being played by Co-WIN and its developers (19 April 2020, Indian Express) - https://indianexpress.com/article/india/co-win-platform-coromnavirus-vaccine-india-modi-govt-7279432/