Covid-19: virus variants and vaccines explained
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Covid-19: virus variants and vaccines explained

By Darcy Jimenez 21 May 2021 (Last Updated May 20th, 2021 16:40)

A number of Covid-19 variants have emerged during the pandemic – but how contagious are they, and will vaccines still work?

Covid-19: virus variants and vaccines explained
Credit: Shutterstock.com

A number of Covid-19 variants have emerged since the start of the pandemic, but one variant has become particularly concerning for experts of recent. The B.1.617.2 variant, first identified in India in February, has led to a spike in coronavirus cases in some parts of the UK, and is believed to be significantly more transmissible than other subtypes of the virus so far identified.

As the UK’s successful vaccination programme continues and coronavirus restrictions are gradually lifted, Pharmaceutical Technology looks at the most significant Covid-19 variants circulating in the UK and across the globe.

India variant

B.1.617.2 is one of three Covid-19 variants that have been discovered in India, and, according to the UK’s Scientific Advisory Group for Emergencies, it could be up 50% more transmissible than the fast-spreading variant first detected in Kent, UK last year. According to Health Secretary Matt Hancock, 2,323 cases of B.1.617.2 have been reported across 127 areas in Britain.

Health experts expect the variant, described by the World Health Organization as a “variant of concern”, to become the dominant form of coronavirus in the UK within a matter of days. Surge coronavirus testing is now taking place across Bolton, Blackburn and Bedford, the areas where some of the highest numbers of India variant cases have been identified.

Though researchers say it has several mutations which could make it resistant to the immune response to the virus, the Prime Minister Boris Johnson said on Wednesday that there was “increasing confidence” existing Covid-19 vaccines will be effective against the newly discovered variant.

UK variant

The UK Covid-19 variant, B.1.1.7, was first detected in Kent in September last year. In December, experts discovered B.1.1.7 was up to 70% more transmissible than existing variants and responsible for a worrying rise in coronavirus infections across the UK. The percentage of Kent variant cases in England leapt from an estimated 3% at the end of October to 96% at the beginning of February.

The spike in B.1.1.7 cases worldwide triggered travel bans in a number of countries shortly after the variant’s discovery, and it has since become the most dominant lineage of the virus in the US, according to the Centres for Disease Control and Prevention. Research has also found that the Kent variant is associated with a higher risk of hospitalisation and death than the original form of coronavirus.

While B.1.1.7 has now been seen in over 100 countries, a real-world study recently found that the AstraZeneca, Moderna and Pfizer vaccines are effective against the mutations found in the variant.

Brazil variant

The Brazil variant, also known as P.1, is thought to have emerged in the country’s state of Amazonas in November. According to analysis by researchers in Brazil, P.1 accounted for 73% of cases in the nation’s capital of Manaus by January. The variant has spread rapidly across Latin America, and researchers recently estimated that it could be up to 2.5 times more contagious than the original version of coronavirus.

Limited data from a trial of a “tweaked” Moderna vaccine suggests the jab could offer good protection against the Brazil variant, and other studies have shown the immune responses driven by the Pfizer and AstraZeneca vaccines are still active, though slightly less effective. Meanwhile, researchers from Brazil and the Yale School of Public Health have found that the inactivated vaccine CoronaVac, Sinovac’s jab candidate, was 50% effective against symptomatic Covid-19 in a Brazilian city where more than three quarters of cases were caused by the P.1 variant.

Further research is required to establish the efficacy of existing, approved vaccines against the Brazil variant.

South Africa variant

Discovered in South Africa in December, the Covid-19 variant B.1.351 appears to have mutations that experts say could make it both more contagious and more resistant to the body’s immune response – but there is no evidence that the variant is more dangerous than the original one.

At least 20 other countries have seen South African variant cases – including the UK, where over 500 cases have been identified.

Trials of the AstraZeneca, Novavax and Janssen vaccines suggest the jabs are, to varying degrees, less effective against the variant, meaning it may be able to escape some immunity. Early research has also indicated, however, that a booster shot of the Moderna vaccine can increase immunity against B.1.351, and the company is currently engaged in a Phase II study to evaluate their modified jab against the variant.