Pfizer Inc’s PFE.N experimental COVID-19 vaccine projects promising result in phase 3 trial, Nov 10, 2020. [Photo: Quartz]

The story of vaccines did not initiate with the first vaccine. It starts with the long history of infectious disease in people. Particularly, with early utilization of smallpox material to provide immunity against smallpox. Edward Jenner utilized substance from cowpox pustules to give protection against smallpox.

Louis Pasteur’s 1885 rabies vaccine was the next vaccine that essentially impacted human disease. Next, antitoxins and vaccines were created for diphtheria, tetanus, anthrax, cholera, plague, typhoid, tuberculosis, and many more through the 1930s.

The middle of the 20th century was a revolutionary time for vaccine studies and development. The capacity for growth of viruses in the laboratory guided humanity to swift discoveries and innovations in finding vaccines such as vaccine for polio. Researchers also paid attention to other common childhood diseases such as measles, mumps, and rubella, and vaccines for these diseases decreased childhood mortality and morbidity. According to World Health Organization (WHO), vaccines prevent an estimated 2 to 3 million deaths every year.

Vaccines contain the same infectious organism that are the source of a disease; for example, measles vaccine has the measles virus. However, these germs are either killed or weakened to the point that they cannot make people sick.  Some vaccines have only a portionof the infectious organism that causes the disease or the genetic material for a specific protein.

A vaccine is a type of preventive medicine that stimulates people’s immune system to produce antibodies prior to getting the disease. After receiving a vaccine, the human body creates immunity to infectious organisms and protects human from specific diseases.

Per Centers for Disease Control and Prevention (CDC), creation and development of new vaccine requires the following steps:

  • Exploratory stage
  • Pre-clinical stage
  • Clinical development
  • Regulatory review and approval
  • Manufacturing
  • Quality control

During the clinical development of a vaccine, people receive a vaccine in three phases. In phase I, a small group of 20 to 100 healthy volunteers who are not exposed to the disease get the vaccine.

If there are not safety concerns from the phase I study, the vaccine enters phase II.  Studies in this phase include more people, where different doses of vaccine are given to hundreds of people with different health and demographic statuses in a randomized-controlled study. The study in this phase would provide us further safety information on common short-term side effects and risks of the vaccine.  Standard and validated testing tools are utilized to assess the immune responses during this phase. A randomized-controlled study would also have a control group. During the study, the control group would receive a Food Drug Administration (FDA) –approved placebo. People who are vaccinated would be compared to the control group in phase II.

In Phase III, thousands of people receive the vaccine to see how efficient and safe the vaccine is. During this phase, the study generates essential information on the effectiveness and safety of the vaccine.

After phase III, vaccine manufacturing companies submit their applications to regulatory bodies, for example, the European Commission or the U.S. Food and Drug Administration (FDA). At this stage, clinical trial data is evaluated for vaccine safety and efficacy. Many vaccines enter phase IV, after the vaccine is approved and licensed for continuous studies to further evaluate its efficacy and safety in the long term.

The COVID-19 pandemic has caused a substantial loss of human life and created challenges to public health, work environment, and food systems worldwide. According to WHO, the COVID-19 pandemic has caused economic and social turmoil; tens of millions of people are on the edge of tumbling into severe poverty. Currently approximately 690 million people are undernourished, and this number might increase by up to 132 million by the end of the year.

As a result, an ideal route to decrease the burden of COVID-19 is the creation of a vaccine that can potentially eradicate the virus. Several institutes are working on developing a COVID-19 vaccine, such as Pfizer and Moderna, where they have made optimistic progress in development of a COVID-19 vaccine.

Vaccine development usually takes years but because of the global emergency due to COVID-19, scientists have been working to fast-track a COVID-19 vaccine. Recently, after reviewing the final efficacy analysis of Phase 3 study, Pfizer and BioNtech SE announced that their mRNA-based COVID-19 vaccine candidates met all of the study’s primary efficacy endpoints. Analysis of the data indicated a vaccine efficacy rate of 95% across different age, gender, race and ethnicity demographics. The observed efficacy in adults over 65 years of age was over 94%.

The Pfizer-BioNTech mRNA vaccine ideally needs to be stored at minus 94 degrees Fahrenheit (minus 70 degrees Celsius). Otherwise it loses its efficacy in around five days at normal refrigeration temperatures of slightly above freezing point.

To deliver and stock the vaccine properly, most countries would need to have the capacity to produce a large amount of dry ice to stock and transfer the vaccine to people at the optimal temperature.

Developing countries such as Afghanistan will have challenges in delivering this vaccine to people. One of the most significant challenge will be that an mRNA vaccine easily breaks apart above freezing temperatures and requires special storage equipment and transportation. 

 

The cost of a vaccine is a critical step toward reaching herd immunity. If the vaccine is expensive and only certain people in a society are able to afford it, the community will not reach herd immunity and the community will not have enough coverage to alter the spread of the virus. Per Forbes, Pfizer and BioNTech have projected the initial price at $19.50 a dose, which comes to $39 per patient for two doses.

Besides the financial burden, transporting of COVID-19 vaccine will be challenging in Afghanistan. Most people in Afghanistan reside in warzones, including places with no roads and electricity, which creates obstacles in storage and transporting the vaccine within the window of its efficacy.

Ministry of Public Health in Afghanistan would need to make a comprehensive plan on how to deliver the vaccine, first to high risk people and then to the rest of the people in the nation.

Author


  • Ahmad Khan has an MD from Kandahar University, Afghanistan. He has a Master’s Degree in Healthcare Quality from George Washington University. Ahmad Khan lives and works in the United States of America.