Covid-19: Medical Discussion

 

​(The information on this page, which is intended for health care professionals, has been supplied by Dr Michael Kamdar, Covid-19 Advisor to the BRANNGO Health Working Group, and Chairman of Friends of Nepal Ambulance Service).

Introduction
The SARS-CoV-2 virus has been at the centre of health, political and economic decisions since November 2019. Mortality rates vary between country, health status and age; it would be unreliable to comment on the actual figure currently. It has been widely reported in newspapers and discussed at length in scientific papers. However, there are many unknowns. The purpose of this page is to inform you, the reader, of some of the scientific knowledge to better inform policy within your organisation that operates in Nepal. It should not be taken as strict guidance due to the lack of peer review and it not being specific to your organisation.

Structure
The full name for the virus is Severe Acute Respiratory Syndrome Corona Virus, and is the strain that has caused COVID-19. The virus structure is a positive sense, single strand of RNA. This RNA is enveloped in a lipid membrane. Kampf has shown that 95% strength alcohol has the potential to reduce clinical viral activity in other enveloped viruses. (Kampf, 2018). However, as this is a novel virus it could in fact be too early to suggest that alcohol rubs are effective as it is mainly respiratory spread (Berardi et al., 2020). Do note that non-alcohol rubs are not currently recommended.

Transmission
According to the WHO website there are 3 main methods of transmission, with small evidence for others:

1) Contact and droplet transmission
This is where the virus is inoculated by respiratory secretions which are between 5-10 micrometres in size. These are caused by talking, singing, sneezing, or coughing. Droplet transmission can occur at distances less than 1m from the infected.

2) Airborne transmission
This is where secretions are <5 micrometres. These are called aerosols. These remain suspended in air for a long period of time and can be moved over large distances. These can occur during medical procedures such as non-invasive ventilation and cardiopulmonary resuscitation. There is the potential that these can be caused by singing, exercising however, more research is needed in these areas.

3) Fomite transmission
This is where the virus is deposited onto a surface. Depending on the type of surface, ambient temperature and other conditions SAR-CoV-2 may become inactive.

4) Others
There have been a few studies that have cultured SARS-CoV-2 via urine and stool. Faecal oral transmission cannot be ruled out.

Clinical Symptoms
SAR-CoV-2 infection should be considered when there is a new high temperature (>38 Celsius), continuous cough, anosmia (loss of the smell sensation). Other symptoms can also include abdominal pain or diarrhoea.

Testing
• Current testing involves sampling the oropharynx by a swab. This is known as RT-PCR, or Real Time Polymerase Chain Reaction. This is where the sample is put through different conditions using different temperatures and enzymes to create new copies of the virus. Radioactive isotopes are attached to a marker label which then attach to the virus. These can then be detected. These are the most widely used tests.
• There are also antibody tests, but these will not detect if a patient is currently infected. They are generally more specific and sensitive weeks after infection and only when there is a reasonable immune response to the virus.

References:
Berardi, A., Perinelli, D. R., Merchant, H. A., Bisharat, L., Basheti, I. A., Bonacucina, G., . . . Palmieri, G. F. (2020). Hand sanitisers amid CoViD-19: A critical review of alcohol-based products on the market and formulation approaches to respond to increasing demand. International Journal of pharmaceutics, 584, 119431-119431. doi:10.1016/j.ijpharm.2020.119431

Kampf, G. (2018). Efficacy of ethanol against viruses in hand disinfection. J Hosp Infect, 98(4), 331-338. doi:10.1016/j.jhin.2017.08.025