One of the biggest public health challenges in 2021 will revolve around immunisation of up to 30 percent of the Malaysian population to protect against Covid-19 infection and severe disease (based on current agreements with Pfizer/BioNTech and COVAX initiative). Political, public, and economic interests in the procurement of vaccines have intensified following positive Phase 3 trial results of three vaccine candidates (Pfizer/BioNTech, Moderna, and AstraZeneca/University of Oxford).
Proving that the vaccine works to regulators, along with short-term safety data, is the first hurdle. Clinical trials take place in a controlled environment overseen by trial administrators. If approved, the vaccine will ultimately be administered by healthcare workers to a larger, diverse population across rural and urban settings. This is where all aspects of immunisation safety will be tested, including maintaining quality and monitoring safety of a new vaccine.
All vaccines listed on the Malaysian National Immunisation Schedule, such as for tuberculosis, hepatitis B, or polio, should be transported and stored between 2 to 8°C or at fridge temperature. Frozen storage between -50°C to -15°C is required for chickenpox or shingles (varicella-containing) vaccines, which are not listed and rarely handled in public vaccine distribution networks, with most utilisation concentrated in private settings. The Pfizer/BioNTech vaccine candidate’s ultra-cold storage requirement has raised the bar, even in high-income countries.
While reassurance has been made that ultra-cold freezers are available in the country, maintaining vaccine quality hinges on a chain of activities, rather than a single activity. The cold chain starts from manufacturing, shipping and transport from overseas, distribution down to storage in various health facilities – until the product is prepared for administration. All these steps shape how effective any vaccine will be.
Indeed, it is preferable to not vaccinate than to administer a vaccine that wasn’t stored or handled properly. Exposure to temperature outside specifications causes vaccines to lose their protective effect. Studies have suggested that temperature excursions and personnel mishandling are factors that could explain reduced effectiveness in different locations.
Malaysia enforces regulatory standards, specifically Good Distribution Practice, for manufacturers and importers. For end users, the Pharmaceutical Services Programme published a comprehensive Guidelines on the Management of Cold Chain Products in MOH Facilities in 2019. (In these documents, the reference temperature for freezer storage went no lower than -25°C.)
To avoid loss of health benefits to vulnerable high-risk groups, and wastage of limited resources, regulators and healthcare workers must be given full support and resources to uphold best practices. Some high-risk groups identified by the World Health Organisation live in geographic areas that are hard to reach. In states such as Sabah and Sarawak, we should expect that weaknesses in infrastructure, manpower and electricity supply will demand unique solutions and a greater level of oversight.
Timely access to vaccines is essential, and so is safety monitoring. The International Coalition of Medicines Regulatory Authorities (ICMRA) has urged clinical trials to continue gathering data for up to one year after emergency use approval including for safety. This would complement pharmacovigilance activities of various countries to monitor vaccine safety within their populations.
The cornerstone of detecting safety issues from any medicine is to report such events to regulators; in Malaysia, to the National Pharmaceutical Regulatory Agency. Consumer reporting is available too but may not be widely used due to low levels of awareness and health literacy.
In overstretched health facilities, additional resources to facilitate reporting by all healthcare workers and careful documentation for further investigation is essential. Furthermore, clear communication to the public and healthcare workers will be much needed to avoid misinformation throughout phased rollout of the vaccine.
High-income countries have implemented additional systems to rapidly assess clinically significant or rare side effects from electronic health databases. Without an active surveillance system in place, it is recommended that infrastructure is developed to monitor and track different vaccines that will potentially be administered in Malaysia. Such a system can form the foundation for stronger regulatory oversight in the future.
Immunisation safety is essential to maintain public trust and prevent greater numbers of infection and death. The government should be transparent on the mechanisms that will be laid in place to ensure high-risk groups have access to an effective vaccine, vaccine quality can be reliably maintained, and pharmacovigilance and risk minimization measures are optimised. Regulators, state/district health administrators, and healthcare workers should be extensively consulted in the period leading up to a vaccine being made available.