5 Summary

This week we covered vaccination against SARS-CoV2 and the use of therapeutic antibodies for passive immunisation. Therapeutic antibodies are only used for vulnerable patients and for people with very serious illness.

Antiviral vaccines can be made from inactivated virus or viral components. The most recent vaccines use genes encoding viral components incorporated into a vector, or as messenger RNA (mRNA). The vector vaccines and mRNA vaccines are a more recent technology, but they were the first ones to be approved for general use.

More than 50 different COVID-19 vaccines went through trials in humans. Phase-1 trials assess vaccine safety in healthy individuals; phase-2 trials are on a larger scale and include different populations and demographics; Phase-3 trials assess vaccine effectiveness in real-world situations. Effectiveness is assessed as the percentage reduction in infection in the vaccinated group, compared with an unvaccinated group, although other measures of effectiveness may also be assessed, such as reduced number of disease cases or reduced severity of disease.

The vaccination programme in the UK was rolled out in 2021, prioritising older people and medically vulnerable individuals. As immunity was gradually lost, booster doses of vaccine were needed to maintain protection. Viral variants can evade protection produced by antibodies against previous variants, but there is still considerable protection against serious illness.

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