The Past, Present and Future of mRNA vaccines

The growth of mRNA vaccines - Past, Present and Future

Vaccines immunise the body against unwanted viruses and bacteria, limiting infection. Most vaccines (e.g., inactivated vaccines or live-attenuated vaccines) introduce a dose of a killed or weakened version of a pathogen into the body, resulting in an immune response. However, over the past several decades, mRNA vaccines have been developed by scientists. mRNA vaccines do not require the actual virus or bacteria to be injected. Scientists take a virus’s RNA blueprint and isolate the protein part of the virus from the RNA blueprint which is mainly responsible for infection. This RNA blueprint is used to create messenger RNA. Messenger RNA is put into vaccines, enters cells and instructs cells to build large quantities of the same protein from the virus. From here, the body recognises the foreign protein and creates antibodies; antibodies are kept in the body so that it can react quickly if exposed to the virus again. Compared to other vaccines, the chemistry behind mRNA vaccines is beneficial, as they do not cause illness and are also quicker to produce. However, it has taken over six decades for the first mRNA vaccine to be used in humans. This article will look at how the uncertainties of mRNA vaccines are being overcome, and the growth of mRNA usage in the future.

In 1961, Sydney Brenner, Francois Jacob, and Matthew Meselson founded the molecule mRNA, and discovered that it gains genetic information from the nucleus and gives mRNA transcript to the cell to create a specific protein. Once mRNA had been isolated in 1969, the chemical development of liposomes used for drug and vaccine delivery continued, and by 1990, mRNA findings had significantly grown, as the novel liposomewrapped mRNA was given to mice. Mice were also used as a testing source for influenza and cancer mRNA vaccines between 1993 and 1995. However, during these several decades, humans were not used as a testing source, because uncertainties in the development of mRNA vaccines remained. The greatest uncertainty was the effectiveness of mRNA translation and its stability; mRNA was quickly degraded and taken up by the body before it could pass the RNA transcript to cells. This was soon solved from advances in nanotechnology in 1995-2005, involving the development of lipid nanoparticles that enclosed mRNA, allowing mRNA entry into cells without degrading.

Recently, particularly during the Covid-19 pandemic years, there has been significant growth in the use of mRNA vaccines in humans. When the coronavirus arose in 2019-2020, a vaccine was key to settling the crisis. Vaccines not only needed to immunise people but had to be produced quickly. mRNA vaccines, which had been hidden in previous years, became a leading chemical resource in the SARS-CoV-2 vaccine race. mRNA vaccines are quick to produce, as they do not require the chemical production of an infectious virus. The vaccines are also easily adaptable and often only take a fortnight to make once scientists attain the virus’s RNA sequence. These discoveries about mRNA technology had already been made before the pandemic, thus the past provided a foundation for rapid growth of mRNA vaccines. Furthermore, from 2014-2019, researchers such as of the US National Institute of Health had worked specifically on coronavirus vaccine development, as the world had already experienced two variations of coronavirus: severe acute respiratory syndrome in 2003, and Middle East Respiratory Syndrome in 2012. Dr. Kizzmekia Corbett and others therefore explored some RNA sequences of covid variations and looked at the “spike protein” of coronavirus and its relevance in mRNA covid vaccine growth. As Professor Shabaz Mohammed (University of Oxford) said, “this pre-existent work allowed us to react rapidly at the beginning of the COVID-19 pandemic”. Pfizer’s COVID-19 vaccine was proven as extremely effective and safe, and it is the first mRNA vaccine with complete FDA approval in the U.S., an evident sign of growth in mRNA usage. Since Covid-19, mRNA vaccines have become a promising and reliable prospect for the future in medicine advancement, primarily because of their easy adaptability and the speed with which they can be produced. These benefits mean that there is plenty of opportunity to grow and develop mRNA vaccines beyond Covid-19, and to tackle some of the biggest health problems in the world. For example, HIV is one of the Big Three Infectious Diseases, and the HVTN 302 study (National Institute of Health, March 2022) tests three HIV mRNA vaccines. The NIH’s three chemical formulae will aim to present the spike protein of HIV, encouraging an immune response from the body. A trial is expected to happen in July 2023. Following the success and safety of Covid mRNA vaccines, chemists predict that mRNA vaccines for diseases like HIV and cancer, could also be safe if using similar methods when being made.

-Jiya