By Brenda Coromina
Currently, there is a COVID-19 vaccine supply problem that disproportionately affects low- and middle-income countries, said Vish Nene at a town hall meeting at the International Livestock Research Institute (ILRI) in July. Only vaccines that are on the World Health Organization (WHO) emergency-use listing (Pfizer, Moderna, AstraZeneca, Johnson and Johnson, Sinipharm, and Sinovac) are made available through the COVAX facility which aims to achieve equitable access to vaccines in response to the global disparity. Despite the challenges, COVAX has been proactively looking at the supply chain and manufacturing aspects of vaccines to enhance their supply and eventually expand manufacturing capacities to low-resource countries. The more vaccines there are on the listing, the greater the roll-out prospects become.
There is still much to learn about the current mRNA vaccines, said Nene, and although we know more about protein-use vaccines (recombinant protein vaccines), they require adjuvants (an ingredient in vaccines that help create a stronger immune response) which may eventually be a limiting factor. Notably, research supports that mixing and matching 2-dose vaccines like AstraZeneca and Pfizer provides a greater immune response than two doses of the Pfizer vaccine. All of the listed vaccines protect against severe disease, hospitalization, death, medical strain, and provide sufficient protection against variants. The duration of immunity is still unknown. The WHO has additionally been coordinating the global response to the variants, consulting various task forces on the issue.
In related news, ILRI has been researching the immune responses to SARS-COV-2 and vaccination using serology. In collaboration with the University of Washington, the project, led by Anna Lacasta-Marin, aims to discern past COVID-19 infection in individuals, and whether the vaccine worked on recipients.