By Dr.Yasuhiro Kanatani, MD, PhD
COVID-19, a biological weapon?
Anthrax, Ebola, Plague, Smallpox, and Botulinum are considered extremely high-risk pathogens to be used as biological weapons. As a consequence, the development of vaccines and therapeutic agents has been more focused on countering other kinds of pathogens. Using micro-organisms as biological weapons requires appropriate measures (detection, prevention, treatment). Therefore, coronaviruses causing SARS (Severe Acute Respiratory Syndrome) or MERS (Middle East Respiratory Syndrome), for which there are no effective preventive measures, are unlikely to be used as biological weapons.
First development of the COVID-19 response in Japan
The first step in responding to COVID-19 in Japan was to quarantine passengers on the massive Diamond Princess cruise ship, which arrived in Yokohama on February 3, 2020. The Ministry of Defense dispatched Self-Defense Forces personnel to the vessel from February 6. A total of 2,700 JGSDF personnel were dispatched during 46 days for medical support activity, but none of them got infected through this mission. The reason for this low infection-rate is that (1) everyone was using protective clothing, (2) it was mandatory to wear goggles, and (3) action was organized by groups of two. Moreover, the use of a passenger boat as a base allowed to secure infection control by reducing the risk of exposure and gave also the opportunity to have a 14-days isolation facility for JGSDF members after the activity was completed. Above all, it is important to mention that staff was promptly supported by the equipment necessary for infection control. It was also essential to secure communications for support activities onboard the cruise ship, and to prevent any failure from the communication equipment due to the robust structure of the cruise ship. This situation convinced the government of the importance of having a hospital ship.
Preventive measures and testing
The next step was to control the spread of the COVID-19 in the community. Countermeasures have been implemented regarding emergency medical transportation, diagnosis, treatment, and prevention of infected persons. When it comes to emergency transportation measures for patients suspected of COVID-19 infection, standard infectious disease preventive measures are taken in cooperation with the public health center and the patient is transported to the designated infectious disease medical institution. Some ambulances are equipped with ozone gas decontamination equipment, but the exact effects on COVID-19 are still unknown. Thus, decontamination is done with 0.1% sodium hypochlorite and wiped with ethanol. Furthermore, prompt screening and isolation of suspected infected people minimize the spread of the infection. Therefore, PCR tests were widely used in Japan at an early stage while antibody test are now considered for surveillance in the epidemic phase. However, the antibody test kits have not been approved yet by the authorities as in vitro diagnostics. As for treatment, Favipiravir1 is offered under compassionate use to patients with COVID-19. Currently, the use of Favipiravir is kept under medication control and is limited to hospitalization. Since it is known that Favipiravir suppresses intracellular growth of COVID-19, the intake of this medication should occur at the early stage of infection. Therefore, from March 31, the phase III of clinical trials for the approval of Favipiravir as a COVID-19 treatment has been initiated. However, since this drug is usually taken orally, in the case of COVID-19 patients attached to artificial ventilators it it should be dissolved and administered via the gastric tube. Thus, in the most severe cases, its effectiveness is reduced.
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