Vaccine Hopes and Doubts
Written by Dallas Vein Specialists on July 20, 2020
The genetic sequence of the COVID-19 virus (SARS COV 2) was first sequenced in laboratory in January of 2020. Since then huge efforts have been applied to progressing to a vaccine against the disease. Such a vaccine, if it works to provide long term immunity to the infection, is the best hope of elimination of the scourge of this disease by providing “herd” immunity. Researchers and laboratories across the globe are racing to produce such a vaccine. Never in the history of medicine have so many focused so much on one goal.
Prior research on SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome), both caused by coronaviruses, has provided some insight to approaches to the development of a vaccine. The coronaviruses have spike structures, the S proteins, on the surface of the virus. These S proteins attach to the human cell and enable the virus to invade by delivering its genetic information into the host cell and highjack the cell’s replication process to make more viruses. A vaccine that would produce antibodies to the S protein would stop the virus and its reproduction.
The course to a safe vaccine is a rigorous one with first tests in animals to determine if it works and is safe. This may take a matter of months. Next come human trials with phase I to evaluate the safety in humans, then phase II to prove effectiveness and proper dosage, and then phase III with a larger group of human subjects to finally establish safety and efficacy. Phases II and III may take a year or more. Then of course it will take time to produce enough vaccine and time for distribution.
Then finally, how effective will a vaccine be? At this point no one knows how well any vaccine will work and for how long it will give immunity, i.e. how long will the antibody response to the vaccine last. From knowledge gained from other closely related coronaviruses, immunity may decrease with time after infection but is detectable over a year later. There are over 100 candidate COVID-19 vaccines in various stages of development at present. At this point in time we do not know when a vaccine will be available and, perhaps even more important, how dependable a vaccine will be in delivering lasting immunity against this disease.