Faulty calculation

    796

    IT WILL take till 2033, some people say, for the Philippines to achieve herd immunity from COVID-19. They make this calculation on the basis of the number of vaccinations per day that the national government is logging using, it seems, donated vaccine doses coming from China or the COVAX project of the WHO.

    Actually, from the Zoom meetings I get to attend, it seems that vaccine doses ordered by the private sector are going to arrive beginning this quarter all the way to the end of the year. These are the AstraZeneca vaccines that Go Negosyo took the lead in negotiating.

    And there’s also the Moderna vaccines that ports and casino mogul Enrique Razon is arranging for.

    As for what the government has ordered? Nothing much has been announced in the press.

    Or maybe I’ve just missed the announcements? But no, I have not seen any vaccination plan that intends to attain an inoculation level equal to 70% of the population, the minimum level we are told that is required to achieve “herd immunity.”

    All I’ve noticed is how often the term “whole of nation” is bandied about, a term turning out to be meaningless.

    ‘The error lies in the fact that herd immunity is not achieved simply by being able to vaccinate 70% of the population; it is achieved by being able to vaccinate 70% of the population at almost the same time such that this large number of the population is rendered immune from any infections, effectively denying the virus enough hosts
    in which to replicate and multiply.’

    Based on the calculations ordinary citizens are doing using numbers of individuals (mainly frontliners) given the vaccine in the last two weeks, we are told that it will take years before the Philippines reaches the levels required. But the calculation is faulty, and not on the basis of dividing 70 million by the average number of those vaccinated per day in the last weeks: that’s correct but that’s not where the error lies. The error lies in the fact that herd immunity is not achieved simply by being able to vaccinate 70% of the population; it is achieved by being able to vaccinate 70% of the population at almost the same time such that this large number of the population is rendered immune from any infections, effectively denying the virus enough hosts in which to replicate and multiply.

    In short, it’s not just how many you vaccinate, but when. If the last of the target population is not vaccinated while the first ones vaccinated remain within the efficacy period of the shots, then hitting the 70% mark is irrelevant.

    So imagine if the vaccines are only good for one year, like the annual flu shots we get. If you vaccinate 25 million on year one, and another 25 million on year two, by the time you finish your second year vaccination program many of those vaccinated on the first year will need to have their shots again. And when you do your third year for 25 million, the first 25 million will be back to square one, as if they hadn’t been vaccinated in the first place. Add to that those of the second group of 25 million for whom the vaccine is losing its magic powers!

    That’s no way to achieve herd immunity.

    This is why US President Joe Biden wanted to have 100 million Americans vaccinated in the first 100 days of his term, and seeks to achieve their 70% target before the end of the third quarter of this year. You can’t stretch out that 70% target over more than a year, otherwise you’re back to square one.

    Of course, the other way to achieve herd immunity is for the same number of individuals to get infected by the virus. By the looks of it, the rising number of infections in the Philippines may make this the quicker path to attain herd immunity than through the nebulous vaccination program. Now we all know how disastrous a nationwide spread of the infection will be – but are we heading this way?

    One year from the day we first started going into lockdown it seems we are facing a new wave of infections that can be worse than the first. Within that one year we never worked on a single tracing system (it seems every store and every mall has one of its own!), we never worked on reserving vaccines early (now we are scrambling to do so!), and all of these because one year ago our leaders were more focused on shutting down ABS-CBN and dismissed the coronavirus as something that could just be slapped away.

    Indeed, from Day One, our calculations have been faulty. And that’s why the whole nation is still paying the price.

    Stay safe. Stay healthy. Stay hopeful.