MEDICINE FOR ALL

Immunogens used to develop viral vaccines:

Whole inactivated virus:

• Inactivated dead virus
• Induces strong antibody response
• Requires large quantities of virus
• Influenza, rabies, hepatitis A

Immunogens used to develop viral vaccines

Attennuated live virus:

• Live virus but doesn’t cause disease
• Induces same response as natural infection
• Not recommended  for pregnant women and immunocompromised persons
• Measles,  rubella, mumps, yellow fever, smallpox (Vaccinia)

 How vaccines are delivered?

• A vaccine can be administered through different routes, for example injection in the muscle or under skin or via the oral route
• Vaccines sometimes require more than one dose to:

1. build complete immunity
2. give a “booster” dose when immunity wears off
3. immunize people against viruses causing disease that may be different from season to season, for example, the yearly flu vaccine

How vaccines work?

• Vaccines greatlynreduce the risk of infection by training the immune system to recognize and fight pathogens such as viruses or bacteria.
• Vaccines safely deliver an immunogen which is a specific type of antigen that elicits an immune response, to train the immune system to recognize the pathogen when it is encountered naturally.

Why we use vaccines?

• Vaccines can prevent infectious disease. Examples of vaccine-preventable disease are: measles, polio, hepatitis B, influenza and many others.
• When most people in a community are vaccinated against a disease, the ability of the pathogen to spread is limited. This is called ‘herd” or “indirect” or “population” immunity.
• When many people have immunity, this is also indirectly protects people who cannot be vaccinated, such as very young babies and those who have compromised immune system.

The virus outbreak presumably originated via a zoonotic transmission linked to the seafood market in Wuhan (China) and later accelarated with human to human transmission, causing the severe subsequent outbreak. Since the original outbreak, SARS-CoV2 has rapidly spread across the world and, in January 2020, The World Health Organization (WHO) declared COVID-19 a global public health emergency. 

In late November 2019, a serious form of pulmonary illness originated in Wuhan City (Hubei province, China) an engulfed a majority of the world. This pneumonia outbreak was attributed to a novel coronavirus, a lipid-enveloped RNA virus, which was named by the International Committee on Taxonomy of viruses severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). The disease caused by the virus was termed coronavirus disease-2019 (COVID-19).