** People don't need more government servants to make election cheating easier ** Bangladesh ranks 12th most corrupt country ** Power tariff hiked again ** DITF- 2023 ends with $39.48m export orders ** Children frolicking over a ride taking risks on Tuesday, as two dangerous high voltage transformers remain installed adjacent to a park of Old Dhaka’s Laxmi Bazar St. Gregory School. NN photo ** What action has been taken to prevent Dhaka's air pollution ** Blinken criticises settlements but stresses US support for Israel ** IMF approves $4.7 billion loan for Bangladesh ** Amar Ekushey Book Fair kicks off today ** We want to know how corruption is to be eliminated under a corrupt government ** Thousands of leaders and activists of BNP join the party's march programme towards Jurain from Jatrabari with banners, festoons, national flags and party flags in their hands on Monday. NN photo ** Foreign aids disbursement, commitment declined ** Awami League leaders and activists gather at a peaceful rally in front of party's central office at Bangabandhu Avenue in the capital on Monday which was arranged by Dhaka South City unit of Awami League. NN photo ** SSC, equivalent exams from April 30 ** HC issues rule on formulation of policy over handcuffing, shackling of accused ** Zamzam water sales halted temporarily ** SIBL Chairman and AMD resigned ** Dr. Zafrullah honoured by UK organisation ** Rohingyas now become a big challenge for us: RAB DG ** EC wants to know whereabouts of B'baria missing candidate ** Govt would not find way to flee: Fakhrul ** Legal action will be taken against attackers on Engr. Yazdani: Minister ** AL never flees, works for people's welfare: PM ** 2 walk to gallows for violating minor girls ** Corruption a major barrier in ensuring a fair business environment: CPD **

Challenges yet to resolve of SARS-CoV-2 vaccine development

10 July 2020
Challenges yet to resolve of SARS-CoV-2 vaccine development

Dr. Muhammad Torequl Islam :
Development of a vaccine is a lengthy and expensive process. Due to high attrition, it takes multiple candidates and long time to produce a licensed vaccine. The developers generally follow a linear sequence of steps due to the cost and high failure rates, with multiple pauses for data analysis or manufacturing-process checks.
Moreover, developing a vaccine rapidly requires a new pandemic paradigm, with a fast start and many steps executed in parallel before confirming a successful outcome of another step, hence resulting in high financial risk.
Use of next-generation sequencing and reverse genetics is helpful to cut the development time of most conventional vaccines during epidemics. The severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2)'s vaccine also has some novel platforms.
However, development of a successful vaccine for it poses some challenges for instance-
(i)    The virus's spike protein is a promising immunogen for protection, however, optimizing antigen design is critical to ensure optimal immune response. There are still controversial talks behind the targeting the full-length protein or only the receptor-binding domain of this virus.
(ii)     The exacerbating lung disease due to SARS and the Middle East respiratory syndrome (MERS) is still controversial as it may also occur by antibody-dependent pathway. It can be associated with a type 2 helper T-cell (Th2) response. Thus, requiring a suitable animal model and critical safety monitoring in clinical trials.
(iii)    The protection should be inferred from experience with the previous species (e.g., SARS and MERS vaccines), those are yet to be established. Generally, the potential duration of immunity is unknown for a naturally acquired infection, whether a single-dose vaccine will be effective or not to be assured.
(iv)    It is difficult to predict where and when the outbreaks will occur and to prepare the trial sites to coincide with vaccine readiness for testing. If multiple vaccines are ready at a same time, it will be important not to crowd sites or burden countries and their ethics and regulatory authorities with multiple trials, which was seen with Ebola vaccines during the 2013-2016 outbreak.
(v)    Having a high-mortality rate, it is difficult to conduct randomized, controlled trials with placebo groups; in fact, other approaches that are scientifically feasible, they're also typically slow, therefore, it should be harder to interpret the obtained data.
(vi)    Many vaccine development organizations are new and are yet to establish financial mechanisms and instruments to support the vaccine development process, additional funding sources should be required to provide the needful supports for the development and scale-up the manufacturing processes. Many vaccine candidates will be developed as by-products alongside the established one, there will no global entity responsible for financing or ordering vaccines from these kinds of manufacturers.
(vii)    To establish a globally fair vaccine-allocation system, clinical and serologic studies should be required to confirm the populations with the highest risk. Although it's unlikely, if the pandemic appears to abruptly end before vaccines are ready, significant financial losses will be a critical component of future pandemic preparedness.

(Dr. Muhammad Torequl Islam is Assistant Professor, Department of Pharmacy, Life Science Faculty, Bangabandhu Sheikh Mujibur Rahman Science and Technology University. E-mail: [email protected])

Add Rate