Coronavirus

• Coronaviruses are named for the crown-like spikes on their surface. There are four main sub-groupings of coronaviruses, known as alpha, beta, gamma, and delta.
• Human coronaviruses were first identified in the mid-1960s. The seven coronaviruses that can infect people are:
• 229E (alpha coronavirus)
• NL63 (alpha coronavirus)
• OC43 (beta coronavirus)
• HKU1 (beta coronavirus)
• MERS-CoV (the beta coronavirus that causes Middle East Respiratory Syndrome, or MERS)
• SARS-CoV (the beta coronavirus that causes severe acute respiratory syndrome, or SARS)
• SARS-CoV-2 (the novel coronavirus that causes coronavirus disease 2019, or COVID-19)
• People around the world commonly get infected with human coronaviruses 229E, NL63, OC43, and HKU1.
• Sometimes coronaviruses that infect animals can evolve and make people sick and become a new human coronavirus. Three recent examples of this are 2019-nCoV, SARS-CoV, and MERS-CoV.

COVID 19

SARS-COV-2 is an oily spherical particle containing a single-stranded positive sense RNA of about 30kb wrapped and coiled by the Nucleocapsid protein.The virus outer shell consists of three structural glycoproteins, spike, envelope, membrane and a lipid coating. The spike protein serve as a receptor binding domain for antibodies against COVID-19.

COVID-19 disease is defined as illness caused by a novel coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; formerly called 2019-nCoV), which was first identified amid an outbreak of respiratory illness cases in Wuhan City, Hubei Province, China.

On March 11, 2020, the WHO declared COVID-19 a global pandemic, its first such designation since declaring H1N1 influenza a pandemic in 2009.

Case Fatality Rate of COVID 19 globally, Africa and Nigeria, 2.1%, 2.7%, 2.1% respectively

Incubation period is 2-14 days

Other Coronaviruses

SARS (2002 -2003)

• Now contained, predominantly affects the lower respiratory tract
• Has a CFR 10% and > 50% mortality in those older than 60 years

MERS

• Also predominantly affects the lower respiratory tract
• CFR 35%
• Linked with direct Carmel exposure

• Respiratory droplet: large droplet- 3feet medium-6 ft
• Hands to mucus membrane contact- sticks to skin easily
• Airborne - unlikely via cough but likely with endotracheal intubation of infected patient, sunctioning, use of nebulizer etc
• Viable for approximately 3 days on solids, 24 hours on cardboard and 3 hours if aerosolised

Most people infected with the virus will experience mild to moderate respiratory illness and recover without requiring special treatment. However, some will become seriously ill and require medical attention. The following are factors that predisposes the host to come down with serious infection

• Age - increasing
• Gender M>F or F>M
• Occupation- health care workers, Travellers
• Race- Black/White Africans, Arabs, Europeans, White/Black/Latin/ Americans, Hispanics, Asian
• Co-infection with other viruses (HIV/HBV/HPV/HERPES)
• Co-morbidities- Cancer, Obesity, cardiovascular diseases, Diabetes, COPD, Asthma
• Virus targets the host’s respiratory system, immune system, CNS, Ophthalmic system, GIT

Host protective factors

• Immune System & Response
• Protective Antibodies/Memory cells
• Immune Status/Competence
• Exercise- Vigorous, rapid, specific and focused
• Adequate Nutrition: - Fruits/Vegetables

• Physical environment- poor air quality, overcrowding, winter/harmattan and rainy season, effect of climate change, effect of urbanization and encroachment on animal habitats
• Chemical factors- air pollution, release of particulate matter
• Biological factors- due to encroachment of animal habitat, increase in man contact with wildlife (Bat cave)
• Psychosocial factors- hugging, handshaking, congregation in social gathering, institutionalization

Vaccination:

COVID-19 vaccines

There are four types of COVID-19 vaccines:

• Whole virus vaccine- the whole virus vaccine uses a weakened or deactivated COVID-19 pathogen to trigger protective immunity .Examples are Sinovac and Sinopharm,
• Protein subunit- include harmless pieces (proteins) of the virus that cause COVID-19 instead of the entire virus. E.g. Novavax
• Nucleic acid- The COVID-19 RNA vaccine consists of mRNAmolecules that codes for parts of SARS-CoV-2 virus, once injected into the body, the mRNAinstructs the cells to produce antigens which are then detected by immune cells triggering a response by the body’s lymphocytes. E.g. Pfizer-BioNTech and Moderna
• Viral vector vaccines uses a harmless virus, different from the one the vaccine is targeting, to smuggle the instructions for making antigens from the disease causing virus into cells triggering protective immunity against it. Viral vector-based vaccines do not contain antigens but uses the body’s own cell to produce it. E. g Oxford, AstraZeneca, and Sputnik vaccines

Symptoms and signs of COVID

People with COVID-19 have had a wide range of symptoms reported – ranging from mild symptoms to severe illness. Symptoms may appear 2-14 days after exposure to the virus. Anyone can have mild to severe symptoms.

Possible symptoms include:

• Fever or chills
• Cough
• Shortness of breath or difficulty breathing
• Fatigues
• Muscle or body aches and headaches
• New loss of taste or smell
• Sore throat
• Congestion or runny nose
• Nausea or vomiting and diarrhoea

Diagnosis

• Clinical based on symptoms and physical examination
• Laboratory:
• Nucleic acid amplification test: such as PCR-based tests, are most often performed in a laboratory. They are typically the most reliable tests for people with or without symptoms.
• Antigen tests: are rapid tests which produce results in 15-30 minutes. They are less reliable than NAATs, especially for people who do not have symptoms. A single, negative antigen test result does not rule out infection.

Treatment

• Most cases are self-limiting and do not require medications
• Mild to moderate symptoms can be treated symptomatically with use of analgesics, oral rehydration therapy, etc.
• Drugs: some antivirals have been approved for treatment of moderate to severe cases. Use of antibiotics in secondary infections. Use of oxygen, intubation, mechanical ventilation etc.

• Disability Limitation
• Rehabilitation by Psychotherapists
• Reintegration back into the society by limiting stigmatization
• Others
• Covid 19 Surveillance