COVID-19: Moderna vaccine 'effective against new variants' © Getty Images

COVID-19: Moderna vaccine ‘effective against new variants’

Moderna said laboratory tests found that vaccination with its jab produced neutralising antibodies against all key emerging variants.

The Moderna coronavirus vaccine, due to arrive in the UK in the spring, is effective against all emerging mutations of the virus that have been detected to date, the company has announced.

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This includes the new strain first detected in south east England that scientists say is more transmissible than the previous variant, and may be more deadly.

Moderna said laboratory tests found that vaccination with its jab produced neutralising antibodies against all key emerging variants, including the South African mutation.

The study showed no significant impact on antibodies against the UK coronavirus variant relative to prior variants.

While there was a six-fold reduction in neutralising antibodies produced against the South African variant, the levels remained above those that are expected to be protective, Moderna said.

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Stéphane Bancel, chief executive officer of Moderna, said: “As we seek to defeat the COVID-19 virus, which has created a worldwide pandemic, we believe it is imperative to be proactive as the virus evolves.

“We are encouraged by these new data, which reinforce our confidence that the Moderna COVID-19 vaccine should be protective against these newly-detected variants.”

The UK Government has purchased 17 million doses of the Moderna vaccine – enough to vaccinate 8.5 million people – but the first doses are not expected to arrive in the country until the spring.

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The biotech company is also launching a clinical trial to test an additional booster dose of its vaccine (mRNA-1273) to study the ability to further increase antibodies against emerging strains beyond the existing primary vaccination series.

The company is also advancing an emerging variant booster candidate (mRNA-1273.351) against the variant first identified in South Africa.

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“Out of an abundance of caution and leveraging the flexibility of our mRNA platform, we are advancing an emerging variant booster candidate against the variant first identified in the Republic of South Africa into the clinic to determine if it will be more effective to boost titers (antibodies) against this and potentially future variants,” Bancel added.

How do scientists develop vaccines for new viruses?

Vaccines work by fooling our bodies into thinking that we’ve been infected by a virus. Our body mounts an immune response, and builds a memory of that virus which will enable us to fight it in the future.

Viruses and the immune system interact in complex ways, so there are many different approaches to developing an effective vaccine. The two most common types are inactivated vaccines (which use harmless viruses that have been ‘killed’, but which still activate the immune system), and attenuated vaccines (which use live viruses that have been modified so that they trigger an immune response without causing us harm).

A more recent development is recombinant vaccines, which involve genetically engineering a less harmful virus so that it includes a small part of the target virus. Our body launches an immune response to the carrier virus, but also to the target virus.

Over the past few years, this approach has been used to develop a vaccine (called rVSV-ZEBOV) against the Ebola virus. It consists of a vesicular stomatitis animal virus (which causes flu-like symptoms in humans), engineered to have an outer protein of the Zaire strain of Ebola.

Vaccines go through a huge amount of testing to check that they are safe and effective, whether there are any side effects, and what dosage levels are suitable. It usually takes years before a vaccine is commercially available.

Sometimes this is too long, and the new Ebola vaccine is being administered under ‘compassionate use’ terms: it has yet to complete all its formal testing and paperwork, but has been shown to be safe and effective. Something similar may be possible if one of the many groups around the world working on a vaccine for the new strain of coronavirus (SARS-CoV-2) is successful.

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