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Viruses and Vaccines

Learn about the immune response to viruses – and how vaccines help.

As the COVID-19 pandemic has made clear, viruses present an ongoing, evolving threat to human health. Our immune systems have various mechanisms to respond to and protect against these threats, but it takes time to generate an immune response, meaning that many viruses can cause serious harm before being removed. Vaccines are an important way that we can stimulate immune responses and prevent serious disease.

In this curated selection of videos and interactive materials from the HMX Pro course on Vaccines and Viral Immunology, you’ll learn about how the body responds to viruses and the role vaccines can play in safely generating a protective immune response.

Please note: HMX online courses in immunology are primarily designed for those working in areas related to health care and the immune system, including diagnostics and treatments. Given the current situation, we’ve decided to make relevant material available to all. We understand that not everyone may have the appropriate background, and we encourage you to use other resources as needed to understand any unfamiliar terms and get the most from this material.


The Immune Response to Viral Infections

In this video, you will see how the immune system responds to viruses, including both the immediate innate response and the slower, but more specific, adaptive response. The video also includes details on the development of vaccines that protect against infection from many diseases. This video features narration from Vaccines and Viral Immunology faculty member Dr. Andrew Pike of Harvard Medical School.

Introduction to Viruses

What are viruses, exactly – and how do they work in the body? In this video, Dr. Shiv Pillai of Harvard Medical School explains the structure of viruses and how they replicate within host cells.

Viral Invasion

There are several steps involved in viral infection. In this interactive animation, you will learn how viruses attach to host cells, the ways they can enter cells, and how viral nucleic material is released.

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Viral Replication

After a virus has invaded a host cell, viral replication can continue. Viruses replicate differently depending on the genetic material they contain. This interactive animation shows some examples of how viruses replicate in host cells, and how virions are then released from cells to infect other parts of the body.

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Immune Responses to Viruses

Once a virus infects a host, the immune system responds. This interactive animation shows how the immune system detects viruses, and gives an overview of the innate and adaptive responses that are initiated to protect cells from further infection. Following infection or vaccination, memory cells and circulating antibodies work to prevent future infection.

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Types of Vaccines

There are many different types of vaccines, which work in different ways to stimulate a strong antibody response to viral threats (as well as protecting against some bacteria and toxins). In this video, Dr. Andrew Lichtman of Harvard Medical School gives an overview of conventional and new vaccine technologies.

Looking for a more in-depth online learning experience? Our foundational immunology course covers key concepts in the field. If you’d like to understand the latest developments in preventing viral infections, consider our advanced course on vaccines and viral immunology. For further background, we have also created an additional free resource focused on innate and adaptive immune responses to viruses.

Looking for more information specific to the coronavirus? Please see the Coronavirus Resource Center from Harvard Health Publishing.