Re: Covid-19: Where are we on vaccines and variants?
COVID-19 Vaccines and COVID-19 Variants
In recent days the effectiveness of COVID-19 vaccinations is being impacted by the emergence of SARS-CoV-2 variants.
These variants could affect not only the effectiveness of the vaccines, but also the natural immunity that COVID-19 survivors have developed, making annual booster shots required for COVID-19 immunity.
Many natural COVID-19 variants have been identified, including the B.1.1.7 variant in the UK, the B.1.351 variant in South Africa, and the P.1 variant in Brazil.
Currently there is no indication that the B.1.1.7 UK variant reduces the effectiveness of Moderna or Pfizer COVID-19 vaccines.
Novavax reported that its vaccine had 85% efficacy with the variant versus 89% with the non-variant strain, and AstraZeneca/Oxford reported that their vaccine has 74% efficacy with the variant versus 84% with the non-variant strain.
The south African B.1.351 variant is potentially more troubling. Clinical trials for the Pfizer and Moderna vaccines indicate a reduction in sera neutralization of the B.1.351 variant, and other studies have shown there could be a six-fold to 10-fold lower binding affinity for antibodies to the variant.
Johnson & Johnson’s vaccine had 57% efficacy with the South African variant, where the variant is prevalent, versus 72% in the US, and Novavax’s vaccine had 49% efficacy in South Africa versus 90% in the UK.
Pfizer and Moderna are already working on developing booster shots for their vaccines to improve their effectiveness against the B.1.351 strain. As there is already some indication of COVID-19 reinfections and possible waning immunity from naturally recovered COVID-19 patients, yearly boosters may be required for COVID-19. However, it is important to note that despite the presence of these variants in the population, the vaccines are still likely to prevent severe outcomes such as COVID-19 related hospitalization and death.
Vaccines can offer a more consistent level of protection and a more robust immune response of neutralizing antibodies. Single-dose boosters provided to patients who have naturally recovered from COVID-19 could increase and extend the duration of their immune response.
But currently, vaccines developed so far may become less effective as new variants of the novel coronavirus spread widely, according to a new study.
Competing interests: No competing interests