Week 8: Variants and immunity

Introduction

At the start of the pandemic there was a lot of concern about how much the SARS-CoV2 virus would mutate, whether this would produce more serious disease, or whether immunity would fail and people would be subject to reinfections, and illness. Later, once vaccines became available, there was a real worry that new variants would completely evade the antibody response produced by the vaccines, and they would have to be reformulated and vaccination programmes carried out every time a new variant emerged.

This week you will be looking into the variants of SARS-CoV2 and how they have partly been able to evade antibody responses. Fortunately considerable immunity has remained from earlier variants and vaccines, and this has provided considerable protection against disease, even if a person is reinfected with a newer strain of the virus.

Download this audio clip.Audio player: Audio 1 Introduction to Week 8

Show transcript | Hide transcript

Transcript: Audio 1 Introduction to Week 8

DAVID MALE

There was a huge sigh of relief, when the first vaccines against SARS-CoV2 became available in December 2020. This was followed by an equally high level of concern when a new viral variant, appeared in Kent in January 2021. This was later designated by the World Health Organisation as the alpha variant. Would it render the recently developed vaccines useless? – Fortunately not, the vaccines continued to provide some protection against reinfection and considerable protection against serious disease. Even when the new strains had mutated to evade some of the serum antibodies, there were still some antibody mediated immunity and good protection against disease from T cells.

In hindsight we can see the evolutionary development of the virus taking place with new strains becoming more efficient at replication, and capable of evading antibodies against earlier strains. No virus has ever been subjected to such detailed genetic analysis and epidemiological tracing. The scientific community has learnt an enormous amount from the COVID-19 pandemic. We now have a better idea of how to slow the spread of a new respiratory virus, how it can be traced, and most importantly how vaccines can be rapidly developed which can protect against disease.

End transcript: Audio 1 Introduction to Week 8

Download

Audio 1 Introduction to Week 8