OIST is collaborating with Ryukyu Shimpo for a series of column articles related to COVID-19 on weekly basis. The forth story was written by Provost Mary Collins.
Article is in Japanese, but please see below the original draft in English.
As explained in last week’s column, when a virus infects a person, their white blood cells start to mount a defense. After about 2 weeks, B cells produce antibodies to bind to and inactivate the virus and T cells evolve into killer cells able to detect and eliminate virus-infected cells. This system has evolved to protect humans from a repeat infection by the same pathogen. The next time the pathogen infects, white blood cells eliminate it before it can establish an infection.
Vaccines work by tricking white blood cells into believing that an infection is under way, so that they make a protective response. Early vaccinations were carried out by a British doctor Edward Jenner in 1796. He injected children with cowpox, a virus from cattle related to the smallpox virus, but which does not cause a serious illness. He showed that these children did not catch smallpox. Smallpox was eventually eliminated worldwide in 1977 using a vaccine similar to cowpox.
There are many effective vaccines against viruses. Some, such as those for polio, measles, mumps and rubella, provide lasting protection following childhood immunization. These are made from weakened strains of the original viruses. In contrast a new influenza vaccine has to be given every year, as the circulating influenza strains change every winter. HIV has provided an insuperable challenge for vaccine design as the virus mutates rapidly, even within a single patient. Fortunately, a combination of drugs that target virus replication can be used to suppress HIV disease.
For us to return to the kind and scope of activities we enjoyed before the pandemic, there is now intense pressure to produce a vaccine against COVID-19. This is an international problem and ideally all countries should work towards an international solution. Vaccines are, in general, more affordable, more reliable and easier to administer than drugs and can be rolled out worldwide, as the successful elimination of smallpox demonstrated.
Fortunately, there is every chance that a COVID-19 vaccine will work. For example, there is a commercial vaccine against a dog coronavirus. However, human coronaviruses that causes common colds are not sufficiently serious for vaccines to have been developed, and SARS, another human coronavirus, was eliminated before a vaccine was needed. Elimination of COVID-19 has not worked the same way because there are so many asymptomatic carriers who spread the virus.
A piece of very good news is that COVID-19 apparently is not mutating substantially as it spreads. More than 100 groups worldwide are developing COVID-19 vaccines for testing using a variety of different approaches. Hopefully, at least one will succeed. Already, a trial vaccine produced in Oxford UK can protect macaques against COVID-19 infection and is being tested for safety in human volunteers.
The final test of any vaccine will be to see if it protects people who are exposed to COVID-19 infection. Here a few questions remain. First, where and when will initial efficacy tests be done? This depends on an ongoing COVID-19 outbreak. Second, if people are protected, how long does the protection last?