{"id":36436,"date":"2025-06-06T16:37:14","date_gmt":"2025-06-06T11:07:14","guid":{"rendered":"https:\/\/www.editage.com\/insights\/?p=36436"},"modified":"2025-06-06T16:46:59","modified_gmt":"2025-06-06T11:16:59","slug":"from-viruses-to-vaccines-understanding-the-science-history-and-controversy","status":"publish","type":"post","link":"https:\/\/www.editage.com\/insights\/from-viruses-to-vaccines-understanding-the-science-history-and-controversy","title":{"rendered":"From viruses to vaccines: Understanding the science, history and controversy"},"content":{"rendered":"

Viruses: Structure, Replication, and Evolution<\/span><\/b>\u00a0<\/span><\/p>\n

Viruses are composed of small pieces of genetic information, either DNA or RNA, enclosed in a protective shell known as the capsid. Some viruses also possess an additional lipid envelope, while those without an envelope are referred to as naked viruses. These viruses require a host to reproduce, and they can survive outside a host for a limited period until the capsid breaks down over time (<\/span>Cleveland Clinic, 2023<\/span><\/a>).<\/span>\u00a0<\/span><\/p>\n

Viruses are the smallest of all microbes in the living world. They can infect a variety of hosts, including humans, plants, bacteria, fungi, and animals, and they inhabit nearly every type of environment, from the air we breathe to the deepest depths of the ocean (<\/span>Harvard Museum of Science & Culture, 2023<\/span><\/a>). Some studies suggest that viruses may date back over 4 billion years, originating in a precellular world as self-replicating entities that evolved into parasites of other cells (<\/span>Harvard Museum of Science & Culture, 2023<\/span><\/a>).<\/span>\u00a0<\/span><\/p>\n

Although viruses are not classified as living cells, they carry genetic material (DNA or RNA) that enables them to hijack a host cell\u2019s machinery to reproduce. This replication process often leads to infection. Viruses enter host cells via one of three mechanisms: 1) Receptor binding, which allows the virus to attach to specific receptors on the host cell surface; 2) Direct fusion, where the virus directly merges with the host cell membrane; or 3) the use of bacteriophages, which inject their genetic material directly into bacterial cells (<\/span>Cleveland Clinic, 2023<\/span><\/a>).<\/span>\u00a0<\/span><\/p>\n

Once inside the host cell, the viral genetic material is released, and it takes over the cell\u2019s machinery to replicate. The host cell begins producing viral proteins and new viral particles. Eventually, these new viral particles are released from the host cell, often destroying the cell in the process, and can go on to infect other cells (<\/span>Harvard Museum of Science & Culture, 2023<\/span><\/a>).<\/span>\u00a0<\/span><\/p>\n

Characteristics of Viruses<\/span><\/b>\u00a0<\/span><\/p>\n

Scientists often describe viruses based on their shapes. The most common shape of viruses that infect humans is icosahedral or polyhedral, which is a geometric shape with many sides, resembling a soccer ball (<\/span>Cleveland Clinic, 2023<\/span><\/a>). This shape is commonly seen in viruses like adenoviruses, which are depicted in Figure 1.<\/span>\u00a0<\/span><\/p>\n

Virus Shapes and Structure<\/span><\/b>\u00a0<\/span><\/p>\n

Viruses can have various shapes, which scientists use to classify them. The most common shapes include:<\/span>\u00a0<\/span><\/p>\n