Table 2.

List of challenges of vaccine supply chain.

Main Category	Code	Challenges	Descriptions	References
Manufacturing challenges	C1	Vaccination cost and lack of financial support for vaccine purchase	The development of a financially affordable vaccine is vital for the successful alleviation of the dangerous COVID-19 pandemic. Vaccination cost and lack of financial support for vaccine purchase for manufacturing and maintaining a cold chain restrict the vaccine development and distribution.	Expert Opinion
	C2	Limited number of vaccine manufacturing companies	To inoculate the global population, a large volume of vaccines is needed. Limited number of companies who can successfully produce effective vaccines is a key challenge, which can restrict vaccination programs around the world.	Pagliusi et al. (2020)
	C3	Lack of accurate vaccine demand forecast	Vaccine demand of a region can be affected by per capita income, vaccine-related convictions, knowledge of medical care staffs, urbanization, and vaccination missions. The inability to predict the variables mentioned above can reduce the efficacy of COVID-19 VSC.	Dizbay and Öztürkoğlu (2021)
Behavioral challenges	C4	Consumers' unwillingness to vaccinate	Consumers can reject vaccines because of fear of potential side effects from vaccines, social dogma, misinformation, and vaccination-related negative beliefs or skepticism.	Khubchandani et al. (2021)
	C5	Inadequate positive vaccine marketing	COVID-19 vaccine acceptance largely depends on the positive vaccine marketing. Inadequate positive vaccine marketing can negatively influence public perception of COVID-19 vaccines.	Expert Opinion
Last mile delivery challenges	C6	Unavailability of volunteers for vaccine trials	As phase II and III need human trials, the lack of volunteers' availability can significantly slow down the development of COVID-19 vaccines.	Richards (2020)
	C7	Long distance between vaccine stores and vaccination camps	A long distance between vaccine stores and vaccination camps can negatively impact vaccine distribution programs.	Antal et al. (2021)
	C8	Lack of proper planning and scheduling	Lack of proper planning and scheduling can influence immunization enrollment, vaccine purchase, storage, and distributions.	Antal et al. (2021)
	C9	Increase in acquisition lead time	Delay in acquisition decisions may increase the acquisition lead time and negatively hamper timely distribution of the vaccine.	Expert Opinion
Cold chain challenges	C10	Lack of proper storage systems	Lack of proper storage system in remote locations can delay the delivery of vaccines, which, in turn, may reduce the effectiveness of the COVID-19 VSC.	Rosen et al. (2021)
	C11	Difficulties in monitoring and controlling vaccine temperature	Some COVID-19 vaccines are temperature sensitive. Inability to maintain the recommended temperature while transferring vaccines from manufacturers to consumers may reduce the efficacy of VSC, especially in the tropical regions.	Lin et al. (2020)
Organizational challenges	C12	Difficulty of tracking vaccinated population	Difficulty of tracking of vaccinated population can reduce the transparency and equal distribution of the COVID-19 vaccine. Countries without a central health registry of their population will face challenges to monitor and track the total number of vaccinated populations.	Hodgson et al. (2021)
	C13	Inappropriate coordination with local organizations	Inappropriate coordination with local healthcare organizations may impede the rapid vaccine supply and distributions by creating communication gaps. Coordination with local organizations is customary for proper distribution of the COVID-19 vaccine and the quick response.	Expert Opinion
	C14	Lack of vaccine monitoring bodies	Lack of vaccine monitoring bodies can hamper purchase, delivery, monitoring, and transparency in the VSC.	Expert Opinion
	C15	Lack of correspondence between the VSC members	Supply chains around the globe are confronting significant interruption, and the lack of correspondence between supply chain members can impede a proper production and distribution of the COVID-19 vaccine.	Zhu et al. (2020)