A COVID-19 vaccine could start rolling out for the public-at-large in a matter of months. This would provide relief from the personal risk of catching the coronavirus.
Yet, it will be more appropriate that the vaccine is not perceived as a personal condom to protect selected individuals from COVID-19, but is used as the mainstay of a programme to eradicate the virus.
Food for thought
There is a clear distinction between a personal prophylactic against disease and achieving population-scale immunity to stop the spread of disease. The real aim of a vaccination programme is to quickly and safely achieve herd immunity to halt the virus’ spread. Enmasse around 65 to 70 per cent of the population, as the scientists tell, must be inoculated (and in quick-time). It also means coordinating the spread of the vaccine at a faster pace than the virus can and to follow a predetermined timeline for complete geographical coverage, so no person left without.
Suppose the approach adopted is different, to administer the vaccine widely but to a very small category of the population (the first responders and essential workers). While these recipients will individually be protected, it may beget a bigger and more dangerous risk. These small number of the vaccinated would still come in contact with the virus and expose it to the effects of the vaccine. While many millions of the unprotected populace remain available as hosts. In turn, this may pose the risk of triggering an aggravated sequence of mutations in this coronavirus.
This coronavirus has already mutated more than 300 times in less than a year. The biggest fear is that the vaccine may prove ineffective against a future strain of the virus. Reports indicate that these mutations have not undermined the vaccines under development, so far! Therefore, the vaccine should be strategically used as a weapon of mass destruction against COVID-19, and not merely like a bullet-proof jacket for some.
Deployment strategy
The COVID-19 eradication efforts require adopting tactics where the vaccine is deployed like a cluster bomb. It will mean vaccinating 65 per cent of the population in a region, then shift to the next and repeat until the whole country is done. India could conduct this simultaneously in multiple blocks until entire districts and states achieve herd immunity by way of vaccination.
This can be achieved within weeks like we ably demonstrate during the national election. Nevertheless, while maintaining social distancing. For the national election, many thousands of booths are set-up across the country so that each eligible voter has the opportunity; the entire nation is covered in phases and within months. The COVID-19 vaccination programme can be conducted along similar lines. The magic ratio of 65 amounts to around 880 million – not unsurmountable for India which holds the national election to cater for more than 900 million voters.
Deployment tactics
Vaccine coverage of 65 per cent of a population will rid it of the virus. Then, unable to find sufficient hosts to reproduce and spread, its 'R naught' will drop close to zero. The protection from the vaccine will kick-in after a couple of days, and even after, those protected must not travel out into non-vaccinated regions, to minimise exposing the virus to the vaccinated, while it still has other viable hosts to mutate and play its own war games. A partial vaccination programme, or allowing the vaccinated free travel into a viral area may lead to the failure of the new vaccine which may then require another round of development.
To understand some more about administering the vaccine to a population cluster within weeks, let us work backwards with a few assumptions. A vaccine giver could administer a dose every five minutes and work 10 hours a day; then, s/he can inoculate 120 others every day. Two givers per vaccination site can serve 5,000 people in 21 days. This example means, that Delhi with 20 million residents will require 4,000 vaccination sites with 8,000 vaccinators if the exercise is to be completed in 3 weeks.
These sites cannot be the hospitals as they are still overloaded with the pandemic workload. Instead, empty movie halls, schools, malls, even local pizzerias or pharmaceutical shops can be enlisted. More the number of dispersed sites, the better, to avoid crowding... and that will still be a big NO NO! Going to get a vaccine must not result in coming back with the virus.
To organise the schedule, each person in the target population can receive an appointment which they could confirm by making an online payment. If they abide with the schedule, this money (or a share) can be refunded in full. But if they ignore and crowd in before their due date, then the deposit will not be refunded. This could help coerce some discipline and prevent unplanned crowding while easing a bit of the cash flow for the exchequer. It is here, that the high-risk individuals within the target region can be allocated priority since the entire cluster will be vaccinated in a short while in any case.
Monitoring the deployment
During deployment, the vials will need to be monitored all through their transit until it is dosed. Any exposure to inclement conditions and impact damage should be captured at each step where the vaccine exchanges custody - key aspects being temperature-time-shock while in transit. There are enough sensors and loggers that the blockchain can use for such record-keeping. To build in systemic checks, these ledgers could also match doses administered with the usage of syringes, swabs, any diluents, etc. A planned reverse logistics of medical waste for disposal will also benefit from such records.
Connecting the vaccine
A lot of talks has surfaced, in my opinion wrongly conceived, on creating more dedicated cold stores and reefer vehicles. It will be handy to review the capacities involved. In the case of the coronavirus vaccine let us assume that each dose is 0.5 ml. The vaccine can be expected in vials, maybe 4 doses to each and in secondary packaging. WHO has guidelines on vaccine packaging and storage, and a handbook to calculate the space required for vaccines.
Extracts from WHO Guidelines and Handbook (WHO/IVB/05.23 and WHO/IVB/17.06) |
In our example of 4 doses per 2 ml vial, say each vial of the coronavirus vaccine will occupy 20 ml (twenty cubic cms) of space in the cold-chain. A twenty footer reefer container has a capacity of 28 cum and it can hold and transport 5.6 million packaged doses. Less than 4 such reefer containers can hold the supply of 20 million doses for Delhi. At an aggregate level, a total of 1.35 billion doses will only occupy space of 6,750 cubic metres or 3,688 square metres of an area if stowed up to 6 feet height. Even if each dose is 1 ml, double the assumption of 0.5 ml, then these numbers will double. And it will not be needed all at once, but staggered over weeks to match production capacity. So, space is not a problem for bulk haulage or in storage.
If the vial size and packaging is redesigned to suit the scale of operations, then the spacecraft can be further optimised. In the current scenario, as long as daily demand is assured, the supply could actually be done in much larger doses per vial, say 50 or more. It could make the supply chain more efficient and add to overall economics, though the risk also increases. In all, the main supply and storage at vaccine depots require very little capacity and last-mile equipment can shift to new locations. Disposable syringes and other supplies will be the items that will actually take up more volume in transport and storage, but these should be manageable outside the cold chain. Rest assured, the complexity in first- and mid-mile logistics can be handled provided the exercise is planned well in advance.
Last-mile distribution
The key supply chain challenge will be last-mile delivery and ensuring a vaccine holding system at each vaccination site, especially in a country the size of India. These can be passive or active cooling units or a combination thereof. Solar energy cooling can also help. In regions where temperatures fall below 2° Celsius, the storage space may require heating. It is here, where much detailing of implementation and planning, is needed. If the programme is undertaken in phases to achieve cluster-based coverage like for elections, the last-mile equipment could be migrated to other locations as the activity progresses. All such plans will need to be aligned to the supply chain model, whether vaccine supply and medical waste pickup will be every second day, or weekly, etc. The type of vaccine, the temperature required and usable life are other factors.
Meanwhile, we must trust the planners who have tasked this job and ward off the virus as best we can.
Until then, stay safe – stand clear of crowds, wear a mask, keep clean.
(All the above considers vaccine types in -20° or 2° to 8° Celsius range. The -70°C vaccine will require many thousands of specialised insulated boxes with dry ice capability, from vaccine maker to terminal depots. Even then, the last-mile will be under 2-8°C range. Luckily, such insulated boxes can also double to service these needs at each vaccination site at these higher temperature ranges.)
Kohli is the former founding CEO of the National Centre for Cold chain Development
