Understanding COVID-19 (Part 11)
Date: March 28, 2020
1) Disease Name: COVID-19 (Corona Virus Disease 2019)
Virus Name: SARS-CoV2 (Severe Acute Respiratory Syndrome Corona Virus 2)
2) It is a virus in the Corona family, classified as number 7
Numbers 1-4 cause the common cold
Number 5 causes SARS
Number 6 causes MERS (Middle East Respiratory Syndrome)
It is approximately 0.12 microns (120 nanometers) in size, but since it does not exist alone, it often resides with droplets of secretions such as mucus, saliva, and phlegm, known as Droplets, which are 5 microns in size. Therefore, high-quality masks that filter particles of 5 microns can protect against this virus.
3) The virus spreads through saliva droplets from speaking up to about 1 meter and through droplets from sneezing or coughing up to 1.50 meters. This establishes a distance of 2 meters to prevent infection, known as Social Distancing.
4) The virus does not remain airborne for long because it resides with 5-micron droplets, causing it to settle on surfaces and materials, where it can survive for several hours to days. The virus does not penetrate the skin but can pass through delicate mucous membranes, including the conjunctiva, nasal mucosa, and oral mucosa. Therefore, it is advised to avoid rubbing the eyes, picking the nose, and putting fingers in the mouth.
5) The virus can be easily eliminated with soap and 70% alcohol. It is recommended to wash hands with soap for 20 seconds or clean hands with alcohol gel or liquid alcohol with a concentration of 70%.
6) The ability to spread is moderately high, with an R0 value of approximately 1.5-3.5, averaging 2.28, meaning that one infected person can spread the virus to 2.28 others. However, the mortality rate is relatively low at 3-4%, compared to SARS with a 10% mortality rate and MERS with a 30% mortality rate.
7) The virus has an incubation period of 1-12.5 days, averaging 5 days. Therefore, self-isolation for 14 days is recommended to surpass the incubation period. The prominent symptoms include fever (88%), dry cough (68%), fatigue (38%), and productive cough (32%).
8) Background
• December 31, 2019: The first pneumonia case was reported in Wuhan, Hubei Province, People's Republic of China.
• January 8, 2020: The first case (a Chinese national) was reported in Thailand.
• February 29, 2020: The first death in Thailand was reported.
• March 16, 2020: The number of infected and deceased outside China surpassed that in China.
• March 27, 2020: The number of infected in the United States exceeded that in China.
• March 28, 2020: The number of infected in Italy surpassed that in China.

9) Disease Situation in Thailand
Phase 1: January 8 - February 8, 2020: The number of cases doubled every 5 days.
Phase 2: February 9 - March 11, 2020: The number of cases doubled every 32 days.
Phase 3: From March 11, 2020: The number of cases doubled every 3-4 days due to cluster infections from boxing arenas and nightlife venues (pubs, Thonglor bars).

10) Rate of Increase in Infected Cases
• Worldwide: Cases double every 3.8 days.
• Thailand: Cases doubled every 9 days (January 8 - March 11, 2020), but have recently increased to double every 3.7 days after March 11, 2020.

11) Proportion of Infected Individuals Showing Symptoms
Out of 1000 infected individuals, 200 (20%) will show symptoms, and among those with symptoms, 200 individuals will have mild symptoms (80%) while 40 individuals (20%) will have severe symptoms requiring hospitalization, with 6 deaths (3%).

12) Mortality Rate by Age
• Age 0-9: No deaths
• Age 10-19: 0.1% mortality
• Age 20-39: 0.2% mortality
• Age 40-49: 0.4% mortality
• Age 50-59: 1.3% mortality
• Age 60-69: 3.6% mortality
• Age 70-79: 8.0% mortality
• Age >80: 14.8% mortality

13) Strategies Implemented to Combat the Disease
• Strategy 1: Let it run its course (Unmitigated) is based on epidemiological knowledge that when a viral outbreak occurs with a sufficient number of non-fatal infections, known as herd immunity, the disease will cease to spread. For COVID-19, this is estimated to be around 50-60% of the population. The disease will then continue as seasonal infections.
Advantages: Herd immunity allows for open borders between countries.
Disadvantages: There will be millions of infections and patients, overwhelming the healthcare system, resulting in a significant number of deaths (in a country with a population of 70 million, there could be hundreds of thousands of deaths).
• Strategy 2: Lockdown (Suppression)
This is the most stringent approach, prohibiting everyone from leaving their homes (allowing one person per household to go out once or twice a week for essential food or medicine). Travel between communities or provinces is prohibited.
Advantages: The disease will subside within 3 months with fewer infections and deaths.
Disadvantages: It will have severe economic impacts on the population, leading to loss of income and social issues. Importantly, once the disease subsides, the country cannot reopen because there is no herd immunity. If the country reopens, a second outbreak will occur immediately, requiring a vaccine or global herd immunity first.
• Strategy 3: (Mitigation) This approach is a balance between Strategies 1 and 2, allowing for varying intensity from close to Strategy 1 to more intense like Strategy 2, adjusting measures according to the situation over time.
Advantages: Eventually, there will be natural herd immunity or a delay in the outbreak while waiting for a vaccine to be developed. The number of infections and patients will be manageable, resulting in fewer deaths than Strategy 1, and the country can reopen to international travel.
Disadvantages: It will take a long time (6-18 months), causing public frustration and impatience, leading some to advocate for Strategy 2, which has its own drawbacks.

14) Hope
(1) Vaccine: Accelerate the development of a vaccine as quickly as possible, expected to take at least 12-18 months.
(2) Medication: New drugs will take years to develop, while existing medications that have been effective against previous coronavirus strains, such as SARS antiviral drugs, are not fully effective. There are efforts to combine multiple drugs, known as Cocktail therapy, which requires further research.
(3) Virus Mutation: Viruses naturally mutate, which may increase or decrease severity, and in a fortunate scenario, the virus may mutate to become non-pathogenic.
(4) Knowledge about COVID-19: Understanding accurate information to cooperate in following measures without distress and with hope and encouragement to overcome this global pandemic crisis.

Summary
• The most important factor in controlling COVID-19 is the public, not the government, healthcare personnel, or medical equipment.
• If everyone considers "the common good over personal benefit" and "responsibility over rights and freedoms," the COVID-19 situation can stabilize quickly with minimal loss.
• Let us support each other, lighten burdens, and refrain from criticizing one another. Best wishes to all.

By Dr. Chalermchai Boonyalayaporn, Vice Chairman of the Health Commission, Senate, March 28, 2020