Herd Immunity is our ticket out of here

The concept of herd immunity is being severely overlooked by the Health Security Matt Hancock. There is a misunderstanding of the theory, which is creating grave consequences across the country, argues Richard Harper.

Matt Hancock's word is law, thanks to the Coronavirus Act 2020, but it is not yet the truth. In fact, to casual observers it may seem as though there is an inverse relationship between our Health Secretary's proclamations and what people who are not currently in the grips of a delusional narcissistic episode call 'reality'.

There are numerous historical case reports to draw on.

'One hundred thousand tests a day by the end of April'? Only if you count those people who indicated that they might want one and will probably get round to it next week.

'False positive rate of the PCR test below one per cent'? Probably. Is that the same as one per cent of positive results being false? No.

'Hundreds of thousands of deaths without his prescribed interventions'? He should look at Sweden.

At this point the Health Secretary appears less like a learned and wise doctor and more like the country's least attentive Biology A level student. The latest epidemiological concept to have been put through his mangle is that of Herd Immunity (HI). In the Commons recently he stated that the two central claims of the 'so called' Great Barrington Declaration by a bunch of 'supposed' Professors of 'Astrology or something' were false. He went on to say, 'It is not true (that) if enough people get Covid we will reach Herd Immunity'. This will be news to my colleagues George Potter and Adolph Eichhorn who proposed the theory in 1916 or indeed the Chief Scientific Adviser who carefully explained the concept back in March. I do not know what evidence he has to suggest Herd Immunity is not possible for Covid. Perhaps it got lost along with those sixteen thousand PCR positive cases and the reams of evidence on 10 pm pub closures. It is possible for every other contagious disease there has ever been.

He refers to 'increasing evidence of reinfection' and how this means we should 'have no confidence we would ever reach Herd Immunity even if everyone caught it'. Well according to the WHO there have been around six hundred million Coronavirus infections worldwide and maybe ten documented cases of reinfection. I think I may be getting a clearer idea of what is deemed 'evidence' by this Health Secretary. To emphasise his point that Herd Immunity was a foolish and unattainable goal he listed the 'many infectious diseases (that) never reach herd immunity like measles, malaria, AIDS and flu'. This is, to coin a phrase, 'emphatically false'.

Measles is very infectious, R0 is estimated at around 15, so this means herd immunity threshold (HIT) is remarkably high, around 95 per cent. So, for measles Herd Immunity is transient, it lasts for a year or two and then wanes as new naive population (children) cause the community immunity to drop. Vaccination removes the need to have these lapses in HI every couple of years and protects vulnerable children from this horrible disease.

Malaria is a vector borne disease and does not fit as neatly into Herd Immunity theories. However, in regions of hyper and holoendemic malaria it does form a stable condition where the majority of adults are immune, and illness is at a consistent a stable level.

AIDS was a very bizarre comparison, people who contract HIV, up until very recently, remained infectious and never became immune. Herd immunity requires infected individuals to become immune and cease transmission even if this is only for a short period of time. Interestingly the high mucosal antibodies in women who are classed as 'High Exposed Persistently Seronegative' for HIV may have some relevance to the susceptibility debate and inform seroprevalence assessments.

All these examples demonstrate a misunderstanding of what Herd Immunity is. Herd Immunity is not a state of eradication but of equilibrium where people continue to become infected and, tragically, die but not all at the same time. This does not sound nice but that is life I'm afraid. If you believe this to be a new state of affairs you did not understand the old one. If Matt Hancock really wants to know what 'simply (is) not possible' he should try and prevent all deaths in the UK from all causes, or on a more achievable scale he could track and trace thirty thousand asymptomatically infected individuals in a population of sixty million.

This failure to grasp crucial concepts like Herd Immunity and the false positive paradox is simply not acceptable in a Health Secretary during a pandemic. The fact that one of his deputies at the Department of Health yesterday tweeted out that 'There is no such thing as Herd Immunity' unfortunately indicates that this level of ignorance may be endemic.