Viruses – Vaccines and Antiviral Drugs Study Guide


Viruses are submicroscopic – meaning they can’t even be seen under magnification. The name Virus is derived from a Latin word that means “slimy liquid” or “poison.”

Culturing cells on glass surfaces made it possible to identify those that cause illnesses based on their effects on cells (cytopathogenic effect) and the existence of antibodies in the blood. Cell culture was then utilized to create and manufacture vaccinations.

Understanding the Virus:

  • A virus is a small group of the genetic sequence, either DNA or RNA, encased in a protein coat.

  • A virus cannot multiply on its own, so they attack cells and utilize host cell components to replicate itself.

  • They frequently destroy the host cell in this operation, causing harm to the host species.

  • Viruses have a unique scientific status: neither plants, animals, prokaryotic bacteria, nor single-cell organisms without an identifiable nucleus.

  • They are classified as separate species.

  • Viruses have been discovered all around the world.

  • Antibiotics cannot kill viruses because they lack the same elements as bacteria.

  • Only antiviral drugs or immunizations may remove or minimize the impact of viral infections such as AIDS, COVID-19, measles, and smallpox.


  • Viruses have nucleic acid, either RNA or DNA, and it can be single-stranded or double-stranded in both instances.

  • A protein coat surrounds the nucleic acid in the form of capsids (tiny units) formed differently.

  • The virion is an infective, extracellular (outside the cell) form.

  • Some viruses can also have an enclosure that they acquire when they exit the cell.

Viruses are fascinating because they can only exist within a living cell, and to stay alive and reproduce, they must have a living cell.

The Cycle of Viral Infection

virus cycleSource

Prevention: Vaccines and Antiviral Drugs

Many viral illnesses can be avoided from spreading by following strict sanitary measures such as efficient cleanliness, proper waste disposal, clean water, and personal hygiene. The best way to deal with viruses is vaccination.

1. Vaccine

  • A vaccination is a biological product that boosts immunity against a certain illness.

  • A vaccination often comprises an agent that mimics a disease-causing bacterium and is frequently composed of weakened or destroyed variants of the microbe, its toxins, or one of its surface proteins.

  • The agent induces the body’s immune system to detect the agent as foreign, destroy it, and “remember” it, allowing the immune system to recognize and eliminate any microbes in the future quickly.

  • Vaccines are microbes that have died or been inactivated or purified compounds generated from them.

  • Vaccines come in a variety of forms.

  • Active vaccination using antigen-containing preparations has proven to induce antibody production and boost immunity.

  • Vaccines have proven effective in avoiding frequent epidemics caused by extremely infectious viruses.

  • Vaccines are most effective when targeted against viruses that do not mutate and infect people.

  • Vaccination can help avoid illnesses caused by viruses that are only antigenic and stable in humans.

How vaccines Work Source

2. Antiviral Agents

  • Antiviral medicines are a type of medication used to treat viral infections.

  • Antiviral medications, unlike most antibiotics, do not kill their target pathogen; instead, they suppress its growth.

  • Antiviral drugs are often imitation DNA building blocks which viruses use to build new genetic material genomes as they multiply in number.

  • The majority of antiviral drugs and treatments are intended to treat HIV, herpes viruses (best known for causing cold sores and genital herpes, but also the cause of a variety of other illnesses such as chickenpox), hepatitis B and C viruses, which can cause liver cancer, and influenza A and B viruses.

  • It is challenging to develop safe and efficient antiviral medications because viruses reproduce in the host’s cells.

  • This makes it difficult to develop pharmacological targets that will interfere with the virus without hurting the host organism’s cells.

  • Furthermore, viral diversity is a key barrier to creating vaccinations and antiviral medications.

Difference between Vaccines and Antiviral drugs

The main differentiation between antivirals and vaccinations is that a vaccine stops a virus from invading your body by giving protection, whereas antivirals treat a virus that has already infiltrated your body by delaying the infection process.


  • Vaccination is an effective way of preventing viral infections. Recombinant DNA technology is mostly employed in creating new vaccines.
  • Antivirals are used to treat specific viral infections, but are also susceptible to drug resistance.


1. Why is the development of antiviral drug therapy difficult?

Viruses multiply within human cells by exploiting our biological mechanism. The medicine must enter these infected cells and work on mechanisms critical to the regular functioning of the human body. This frequently results in collateral damage to human cells, which is felt as a side effect.

Viruses are significantly more varied than bacteria, including storing genetic material. There are few effective broad-spectrum antivirals and thus are difficult to develop. Viruses, unlike bacteria, have fewer protein-building components that may be targeted with medicines.

2. What is the difference between an antiviral and an antiretroviral?

Antiviral medications target a wide range of viruses, including herpes, hepatitis, and influenza. Antiretroviral medications, on the other hand, are used to treat retrovirus infections, the most common of which is HIV.

3. How can vaccines be used to prevent viral infection?

Vaccines include a harmless version of the bacterium or virus that causes the disease against which one is immunized. Before being used in the vaccine, the bacteria or virus is either killed or substantially weakened to elicit an immune response without getting one sick.

4. How do antiviral drugs fight viral diseases?

Antiviral medications block the receptors so that the viruses cannot connect to and penetrate healthy cells. They boost the immune system to aid in the battle against a viral illness. These drugs also reduce the viral load, i.e., the number of active viruses in the body.

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  1. Virus Characteristics. Accessed 9 Dec,2021.
  2. Viral Disease. Accessed 9 Dec,2021.
  3. Virus Control Accessed 9 Dec, 2021.

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