New technologies might provide more potent or broader immunity — but will have to fight for market share.
Vaccines against the coronavirus SARS-CoV-2 have been given to billions of people to protect them from COVID-19, and have saved more than 20 million lives. But viral variants can evade some of the immunity provided by the original vaccines. As a result, vaccine developers around the world are working on dozens of ‘next-generation’ COVID-19 vaccines: not just updates of the first versions, but ones that use new technologies and platforms.
These vaccines are a diverse group, but the overarching aim is to deliver long-lasting protection that is resilient to viral change. Some could protect against broader classes of coronavirus, including ones that have yet to emerge. Others might provide more potent immunity, might do so at lower doses, or might be better at preventing infection or transmission of the virus.
Why do we need more vaccines?
In a word: evolution. The first approved COVID-19 vaccines were tested for protection against versions of SARS-CoV-2 that had not changed much since the virus was first identified. These vaccines come in different types — some are composed of messenger RNA, others are inactivated versions of the coronavirus itself or some of its proteins — but all work by exposing the body to antigens (portions of the virus) to provoke an immune response without causing disease.
Broadly speaking, this immune response comes from B cells, which produce antibodies that can block SARS-CoV-2 from infecting cells, and from T cells, which can destroy infected cells (and support other immune responses).
The vaccinations also generate a pool of ‘memory cells’ for prolonged immunity, even after initial antibody levels dwindle. On subsequent infection, memory B cells begin proliferating and differentiating into cells that churn out more antibodies (see ‘How coronavirus vaccines protect against SARS-CoV-2’).
Read more: Nature
