Virally vectored DNA and mRNA vaccines are both in the forefront of news, as the COVID-19 pandemic continues to spread. The virally vectored DNA vaccines at advanced stage include the Oxford/Jenner ChAdOx1 nCoV-19, and the CanSino Biological adenoviruses. Whereas the most promising mRNA ones appear to be Moderna-1273, and the candidate vaccine from UK Imperial College.
Comparing Virally Vectored DNA and mRNA Vaccines
Virally vectored vaccines use inactive, or live but weakened viruses unable to reproduce themselves. These enter the subject’s body cells, causing production of the vaccine antigen. A single dose of the vaccine might be sufficient protection, as is the case with Ervebo EBOLA vaccine. This is the traditional approach to vaccine production, and lends itself to mass production.
However, when comparing mRNA vaccines with those virally vectored DNA ones, we encounter a breakthrough approach. Radically different mRNA vaccines – for example Moderna – trick the subject’s body into producing a natural vaccine by inserting a messenger protein into their system. This is an attractive, safe option that does not use a deactivated or weakened virus.
Which of These Two Prototype Vaccines Can We Use Now?
We ought not to let our guard down on this one, and takes chances with biological science. Both virally vectored DNA and mRNA vaccines are at the advanced testing stage at Oxford and Moderna respectively, but they are not officially safe and there are others in the pipeline.
Oxford and Moderna are both making plans to ramp up to mass production, but we still need to continue to take special care. That’s because a vaccine is not a cure. It is a preventative measure and until we have it we remain at risk of contracting the disease.
If we are young and in good health, then our COVID-19 systems may well be mild and the disease a walk in the park. However, this does not mean we could not infect an older adult – a parent or grandparent perhaps – and they could die because we were careless.
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Preview Image: Candidates for Forming SARS-CoV-2 Proteins
