Nov 13, 2020 Covid19 vaccine update

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November 13, 2020

There is hopeful news this week regarding a vaccine for Covid 19. The Pfizer/BioNTech vaccine has been shown to be 90% effective in preventing Covid 19 infections. This vaccine, like the Moderna vaccine undergoing clinical trials here in Tucson, utilizes a new technology involving messenger RNA.

In brief, cells use DNA as the template to make messenger RNA. Messenger RNA is then translated into proteins which are utilized to perform the essential functions of life.

An RNA vaccine introduces a messenger RNA strand which codes for a specific disease antigen. Antigens are what the immune system react to when mounting an immune response. In this instance, the RNA strand from the vaccine causes cells inside the body to make Covid 19 antigen. This antigen is then displayed on the cell surface, causing the immune system to form antibodies against the virus.

RNA vaccines are a new technology which have some major advantages over the conventional immunization development process. First off, they are much easier and less expensive to make since they can normally be synthesized in a lab. Consequently, they are quicker to produce then conventional vaccines which may need to be grown or cultured in other cells. Additionally, they are generally noninfectious and unlikely to cause an infection.

Like any new technology, there are challenges. First and most concerning is an unintended immune reaction different from the desired one. This though has not been an issue so far with the Covid 19 vaccines.

Secondly, storage for these RNA vaccines is a challenge since currently they require extremely cold temperatures to maintain effectiveness. Administering these vaccines can also be an issue as the RNA can be quickly broken down by the body before it has a chance to work.

RNA vaccines have been in development for a few years, yet up to this point none have been available for patients. The technique is fascinating and is being investigated as a possible therapy for certain cancers as well as for allergies.

It is unclear when actual doses of the vaccine will become available. It is widely expected that the Moderna vaccine will show similar success as the Pfizer product, yet since Moderna has about 10,000 fewer patients in their study it is taking them longer to get to the number of Covid 19 cases needed to show success.

Finally, the number of new cases, hospitalizations and deaths continues to double about every 2 weeks here in Arizona. While our absolute numbers are lower than at our peak back in June and July, the rate of increase is similar. It is imperative that everyone continue to wear a mask while out in public. Likewise, I strongly recommend not to have any family gatherings for Thanksgiving this year, as many of the new cases are developing from these types of small get togethers. Take care and have a good week.