India may need a 49-day lockdown

'We will need more than 21 days of lockdown for sure.'

Dr Ronojoy Adhikari and Dr Rajesh Singh are both applied mathematicians.

Dr Adhikari, professor and scientist from The Institute of Mathematical Sciences, Chennai, is currently affiliated to the Department of Mathematics, Cambridge University, where he is doing research.

Dr Singh is a postdoc in the group of Professor Michael E Cates at the department of applied mathematics and theoretical physics, University of Cambridge.

Both mathematicians are part of the UK's RAMP taskforce, lead by Cambridge mathematicians, Professor Julia Gog and Professor Cates.

RAMP stands for Rapid Assistance in Modelling the Pandemic and is a group of experts in epidemiology and pandemic modelling who have been urgently called in to use scientific modelling to assist in the battle against the COVID-19 pandemic and save lives, by providing mathematical and scientific evidence to inform Britain's government policy.

Dr Adhikari and Dr Singh have just co-authored a paper in which they studied the advance of COVID-19 in India.

According to their paper: 'The impact of social distancing measures -- workplace non-attendance, school closure, lockdown -- and their efficacy with durations' were investigated.

'A three-week lockdown is found insufficient to prevent a resurgence and, instead, protocols of sustained lockdown with periodic relaxation are suggested.'

'Forecasts are provided for the reduction in age-structured morbidity and mortality as a result of these measures.'

'Our study underlines the importance of age and social contact structures in assessing the country-specific impact of mitigatory social distancing.'

Dr Adhikari and Dr Singh speak to Vaihayasi Pande Daniel/Rediff.com about the suggestions in their study, offering answers, they say, based only on their area of competence:

As per statistics available, India is testing way less than even Pakistan per million.
But health experts mention that testing is going on to the full capacity.
Since testing seems to be progressing slowly, the logic, as per the results of your studies, is to extend the lockdown, so spread is contained while testing gets to as many people as possible and up to speed?

Testing is critically important.

Unless we test, we cannot estimate the fraction of the population that has been infected, but is not showing symptoms.

Without this information, mathematical models can only provide bounds, not predictions with quantifiable uncertainties.

Our model operates with the very conservative estimate that the number of actual cases is equal to the number confirmed by the Government of India.

This, of course, is an underestimate.

Even with that assumption, we find that a 21-day lockdown is insufficient.

But, unless we know how many cases there actually are, it is impossible to say with any quantifiable confidence, how many days of lockdown or other social distancing measures will bring the situation under control.

Therefore, yes, extensive testing is the need of the hour.

What kind of lockdown is preferable for India?
Your study mentions either a flat 49-day lockdown or a two-month lockdown with periods of relaxation.
Given the equally important economic issues, the central and state governments would probably prefer the latter.
But a 49-day longer continuous lockdown is far preferable in your view?

Our estimate for the number of lockdowns is a best-case scenario.

We will need more than 21 days of lockdown for sure, but this will have to be adapted to local conditions, and each state will have to decide on a policy that is responsive to the number of cases in that state, the economic implications, and multiple other considerations.

As we have repeatedly insisted, mathematical prediction is but one component of a policy decision framework.

We try to provide the best estimate we can on numbers, but human lives go beyond numbers, and much thought needs to go into how to manage the extended period of social distancing we will need for mitigation.

Are there any other issues with the kind of case data coming out of India?
Is it just low testing?
Or low publication of results?
>Or anything else that is skewing the figures too, do you feel?

This is a very dynamic situation, as new cases, and unforeseen situations like the religious congregation in Delhi are skewing expectations.

We need more data to be publicly available and in real time, so modellers can provide real-time updates of this highly evolving situation.

From whatever information is available to you, do you feel the government, while watching the way the pandemic is evolving in the country, values the importance of consulting experts in epidemiology and pandemic modelling to provide evidence to inform government COVID-19 policy?

Several very senior members of the Indian scientific community have been in touch with us and communicated both their appreciation and the need for further modelling.

We have been told that our work has been brought to the notice of the advisory body to the prime minister.

We are doing further modelling work, with input from RAMP and will be updating the results of our first paper continuously.

Beyond this, we are unable to comment.

You must have studied several situations, the world over, while working on pandemic modelling and what are generally the reasons in parallel situations for low testing?

At present, social distancing is the only tool.

There are two broad exit strategies.

One. is to phase the transition to herd immunity so that the medical system is not overwhelmed by the resulting morbidities and mortalities.

The other is to enforce strict lockdowns to suppress transmission, reducing both morbidity and mortality, and hope that a vaccine becomes available in the time scale of a year, and then mass vaccinate.

I do not want to comment on the implementation, and the comparison with China, as this is outside our expertise.

In absence of a vaccine, social distancing is the only tool a government has to fight this epidemic.
So that means even after this present lockdown in India, which should hopefully be extended considerably beyond 21 days, there might be later a need for another stringent, lengthy lockdown, some months down the line, if re-infection occurs?

That is absolutely correct.

We will need an extended protocol of social distancing till we either have herd immunity (that is most of the population has been infected) or a vaccine has been found.

The time scale for a vaccine to become available is going to be at least a year, so we are really looking at some measure of social distancing (not necessary lockdown, though) that has to be planned for that length of time.

But right now, the most important message you want to get out to India, based on your studies, is that India must not relax the 21-day lockdown and it must extend it?

This is our key message: 21 days of lockdown will not be sufficient to control the epidemic.

We will need to practice social distancing for an extended period of time, informed by mathematical modelling, but taking into account economic, medical, social and ethical constraints, till we have a vaccine or herd immunity is attained.