SARS, MERS, Marburg and Ebola virus and a recent Hanta virus outbreak in China, remind us that the world can carry on without humans.
The vaccine for Covid-19, prepared and ready for testing in 42 days, will be injected into human volunteers in Seattle, USA essentially a rapid response to the current pandemic. Vaccines are made from live weakened viruses or viral proteins cultured in HeLa cells/Avian egg cells. Covid-19 is an RNA virus whose code is simple to reproduce. The RNA code is inserted into human cells to replicate new corona viruses and thereby kill or incapacitate the human host. Host immune cells uptake the corona virus and alert the host immune cells to the presence of corona virus. CueVac, Germany is making batches of RNA, sufficient for many vaccine doses. As yet, no RNA vaccine has been approved for existing diseases. An RNA vaccine for rabies is now undergoing clinical trials. Inovio, a US biotechnology company is developing a DNA vaccine for Covid-19, the DNA generates viral RNA and viral proteins. The target proteins are the spikes which give the virus a crown like appearance under the electron microscope.
China released the entire RNA sequence of Covid-19 by early January with scientists worldwide copying the sequence to make vaccines. The virus uses the spike to attach the ACE2 receptor on cells in the mouth, throat, lungs and intestines. Antibodies and immune cells of a vaccinated individual are expected to notice the spike protein and neutralise the virus.
There are three phases of clinical trials: Phase I a small number of healthy adults are given the vaccine to ensure safety; Phase II trials test safety in a larger group and check for side effects; Phase III thousands of people are tested. All trials are controlled by the European Medicines Agency and the US FDA to decide if the vaccine can be licensed. These trials must be stringent because appropriate testing ensures confidence in the vaccine. Fortunately Sars-Cov-2 does not mutate due to its large genome.
The Covid-19 virus is a warning, human lives will change, perhaps Marburg Virus cf. Marburg University, Marburg, Germany 1976 will adversely affect human existence on Earth.
Source: Irish Times, Life Science, Thursday, March 26, 2020