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Information on new strains of coronavirus, the effectiveness of vaccines against variants of the virus and how you can protect yourself.

How new strains arise

All viruses, including coronavirus, can change over time. This can lead to different strains of the virus with different characteristics. While there are many different tiny changes in the genetic sequence of the virus, there are four main strains (also called variants) which are currently circulating more quickly. The strains first detected in the UK (also known as the Kent strain), South Africa, Brazil and India are each identified through a specific combination of mutations. Even though these variants arose in different places, they share some of the same mutations.

It’s common for viruses to change over time, so it’s not surprising that coronavirus has mutated. When a virus such as COVID-19 enters the body, it begins to multiply quickly. Each time it multiplies, there is a chance that the virus may slightly change. This process is called mutation. More new strains are likely to arise and it's also possible for new strains to mix to create even more new variants.

The Delta variant

B.1.617.2, also known as Delta, first appeared in India in October 2020 and is now believes to be the dominant variant in the UK. Experts believe it spreads more easily than the variant initially discovered in Kent.

Hospitalisations and the Delta variant

On 3 June 2021, Public Health England announced that the B.1.617.2 (Delta) variant may have an increased risk of hospitalisation compared to the variant first found in Kent, but said that more data is needed for them to be confident in this finding.

The Pfizer vaccine and the Delta variant

A study published by Public Health England (PHE) showed that two weeks after the second dose, the Pfizer vaccine was 88% effective in preventing symptomatic cases of COVID caused by the variant first detected in India.

The Oxford vaccine and the Delta variant

A study published by PHE showed that, two weeks after the second dose, the Oxford/AstraZeneca vaccine was 60% effective in preventing symptomatic cases of COVID caused by the variant first detected in India.

The same research, conducted between 5 April and 6 May, showed both vaccines were 33% effective against the variant three weeks after the first dose. So it is really important to get the second dose when you are offered it. 

How to protect against new variants

All the available evidence shows that the best way to protect yourself, your loved ones and your community against this new variant is to:

  1. Remember hands, face, space and ventilation
  2. Take a lateral flow test twice a week and take a PCR test if you display any symptoms
  3. Have both vaccination jabs when invited