The word “vaccine” comes from the Latin word vaccinae, which means “of or relating to cows¹.” It was first used in the 18^th century to describe the mysterious substance in cowpox that appeared to protect humans against the lethal smallpox². Back then, the idea that we can gain protection against a virus by receiving the virus in a weaker or non-functional form might sound wild. Nonetheless—fast-forward to 2020—most of us do not wake up in the morning thinking about dangerous diseases like polio, smallpox, or measles thanks to the development and use of vaccines.

The world has been fighting the COVID-19 pandemic for more than half a year. The new coronavirus—SARS-CoV-2—which causes COVID-19, has taken the lives of at least 500,000 people globally (as of June 29), with a recent surge of cases in South America and Russia³. One of the most anticipated game-changers to alter the course of COVID-19 is the development of an effective vaccine. Currently, we do not yet have a vaccine that is ready to be widely released^4,5,6. And just when you thought the news on media could not get more confusing, it did. What is a vaccine? Do we really need it? Why is it taking so long to make anyway?

While researchers are racing to develop a vaccine by the end of the year, the rapidly changing information overwhelms many of us, triggers confusion and anxiety, and causes some dangerous or unhelpful misconceptions^7,8. Eliminating COVID-19 once and for all is a complex operation that requires fast-tracked scientific breakthroughs and unprecedented global collaboration and coordination among different sectors. Equally importantly, it requires a genuine understanding of what immunity means in the general public. Gaining accurate knowledge is what each of us, as an individual, can and should do to help fight the pandemic. The goal of this article is to help us do our part and avoid contributing to behaviors that slow down our way out of COVID-19.

Let’s break down “why do we not have a vaccine yet” into bite sizes in a three-part series.

What Is a Vaccine?

A vaccine is commonly made using the virus that causes a specific disease—with a twist. The virus is inactive or weakened such that when introduced into the human body, it causes no or very mild symptoms⁹. The seasonal flu shots against the influenza virus, for example, are made with “dead” influenza viruses¹⁰. In addition to the whole virus, small pieces of the virus that are artificially made—also called “biosynthetic” or “recombinant” vaccines—can be used to produce vaccines. For example, the Hepatitis B vaccine contains pieces of the virus made in yeast cells¹¹. More recently, another kind of vaccines has emerged: one that is made with the genetic information of the virus in the form of DNA or RNA—also called “nucleic acid” vaccines. Regardless of how they are made, vaccines train the immune system in our body to recognize and fight specific viruses by making neutralizing antibodies. The human body is a complex machine with memories. Next time, when we are infected by a fully functional and dangerous form of the same virus, your body remembers the training and knows exactly what to do to eliminate the virus quickly.

Vaccination vs Immunization: What Is the Difference?

“Vaccination” is the act of receiving the vaccine¹². “Immunization” is when our body starts to produce antibodies that bind to the virus and develops the defense mechanism against the virus that the vaccine is meant for. And–you guess it–if you get infected by the actual virus and recover from it, you can also become immunized.

Sources and Further Reading

1. “Cowpox.” Wikipedia, 18 May 2020, en.wikipedia.org/wiki/Cowpox.
2. Brink, Susan. “What’s The Real Story About The Milkmaid And The Smallpox Vaccine?” National Public Radio (NPR), 1 Feb. 2018, www.npr.org/sections/goatsandsoda/2018/02/01/582370199/whats-the-real-story-about-the-milkmaid-and-the-smallpox-vaccine.
3. Johns Hopkins University & Medicine. “COVID-19 Case Tracker.” Johns Hopkins Coronavirus Resource Center, coronavirus.jhu.edu. Accessed 30 June 2020.
4. “Draft Landscape of COVID-19 Candidate Vaccines.” World Health Organization, 9 June 2020, www.who.int/publications/m/item/draft-landscape-of-covid-19-candidate-vaccines.
5. Mullard, Asher. “COVID-19 Vaccine Development Pipeline Gears Up.” The Lancet, vol. 395, no. 10239, 2020, pp. 1751–52. Crossref, doi:10.1016/s0140-6736(20)31252-6.
6. Corum, Jonathan, and Carl Zimmer. “Coronavirus Vaccine Tracker.” New York Times, 30 June 2020, nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html.
7. “Six Common Misconceptions about Immunization.” World Health Organization, 19 Feb. 2013, www.who.int/vaccine_safety/initiative/detection/immunization_misconceptions/en/index1.html.

8. Dowdy, David, and Gypsyamber D’Souza. “Early Herd Immunity against COVID-19: A Dangerous Misconception.” Johns Hopkins Coronavirus Resource Center, coronavirus.jhu.edu/from-our-experts/early-herd-immunity-against-covid-19-a-dangerous-misconception. Accessed 30 June 2020.
9. “Vaccine Types.” NIH: National Institute of Allergy and Infectious Diseases, 1 July 2019, www.niaid.nih.gov/research/vaccine-types.
10. Miller, Kelli. “Influenza Vaccine (Flu Shot and Nasal Spray) for Adults.” WebMD, 27 Jan. 2011, www.webmd.com/vaccines/flu-shot-guidelines-for-adults#1.

11. “Recombivax (Hepatitis B Vaccine (Recombinant)): Uses, Dosage, Side Effects, Interactions, Warning.” RxList, 10 Apr. 2019, www.rxlist.com/recombivax-drug.htm#description.
12. “Vaccines: Vac-Gen/Imz Basics Main Page.” Centers for Disease Control and Prevention, 16 May 2018, www.cdc.gov/vaccines/vac-gen/imz-basics.htm.