Virus mutations – herd immunity or partial vaccination not enough ?

On the late news last night, I watched a harrowing report from the Manaus, the capital of Amazonas in Brazil, a city of 2 million people. The hospitals were full and running out of oxygen, and families were caring for their loved ones in hospital corridors, sharing a cylinder of oxygen with 5 other families, with no medical supervision.

Brasilien Beerdigung von Corona-Toten
The number of coronavirus deaths in Manaus is rising again

The fight against coronavirus in Manaus should already have been won. By August 2020, 75% of the population had already been infected with the novel coronavirus — enough for the area to build up solid herd immunity. However, last December, COVID-cases were suddenly spiking again., and hospitals in Manaus are running out of oxygen to keep corona-patients alive. In all probability, people in the Brazilian city have caught the new P.1. virus variant, which manages to “escape” the immune system’s response in some people. Researchers now hope to learn more by sequencing samples from these patients. 

An “immune escape” like this is a serious concern because it could mean that even people who have already recovered from COVID could be infected again, and that the vaccines on the market aren’t effective anymore or need refreshing. The rapid evolution of these variants suggests that if it is possible for the virus to evolve into a vaccine-resistant phenotype, which may happen sooner rather than later. To reproduce, viruses insert their genetic make-up into a host cell. Each reproduction comes with small copying mistakes, and each one of these mistakes in turn changes the virus’s genetic code — it mutates. Vaccines put evolutionary pressure on the virus. The variants of the virus that are selected to continue reproducing are those that manage to evade the immune system by mutating.

Symbolbild DNA-Fehler
Small copy errors occur with each reproduction – the virus mutates

Mutated coronavirus strains could escape a weak immune response and make the pathogen more aggressive. That way, even people who have already recovered could get infected again — and the vaccines would need updating. When weak vaccines are used, however, or the second dose is delayed for too long, the vaccine has the exact opposite of the desired effect. That’s why some experts have criticised the policy of delaying the second dose of the vaccine, which the UK has done and the US is contemplating. Their argument is that more people will build up initial protection this way, but they won’t be able to develop a sufficiently strong immune response. The body will fight the more dangerous virus strains longer, giving the virus more time to evade death through vaccination. When people who have yet to be vaccinated encounter this type of virus, there could be deadly consequences. click full article

Although not suggested in this article, these vaccine theories imply that the natural herd immunity acquired in the first wave in Manaus is not sufficient to provide a strong immune response against of the Brazilian P.1.variant, which probably developed in the City. In fact, this new variant may also be more deadly than the original strain, although lack of adequate care is contributing to the high death rate.

I have not been able to establish if the Brazilian P.1. variant is circulating in Portugal, the very high death rate yesterday (273) in a small country of 10.2 million people suggests that it may well be. This shocking rate is the highest in the World at the moment. If the rate of deaths in Portugal were extrapolated, the UK death rate would be 1,956 (actual yesterday 1,725) and 9,540 in the US (yesterday 3,916). Portugal is in the grip of a “terrible” phase of the Covid-19 pandemic, with no let up expected for weeks, the country’s prime minister has warned in a blunt and bleak assessment of the current situation.

a group of people sitting on a bench: Photograph: Pedro Nunes/Reuters
Ambulances queueing in Lisbon

More than 20 ambulances carrying Covid patients queued outside Portugal’s largest hospital on Wednesday evening as they waited for beds to become available, while doctors in other hospitals warned of a risk of the oxygen support system collapsing. click full article.

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