Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 26 to 30.

WHO has been tracking mutations and variants since the start of the COVID-19 outbreak. Our global SARS-CoV-2 laboratory network includes a dedicated Virus Evolution Working Group, which (26) __________ to detect new changes quickly and assess their possible impact.

Research groups have carried out genomic sequencing of the COVID-19 virus (27) __________ shared these sequences on public databases, including GISAID. This global collaboration allows scientists to better track how the virus is changing. WHO recommends that all countries increase the sequencing of the COVID-19 virus where possible and share data to help one (28) __________ monitor and respond to the evolving pandemic.

WHO has also established a SARS-CoV-2 Risk Monitoring and Evaluation Framework to identify, monitor and assess variants of concern. It will involve components like surveillance, research on variants of concern, and (29) __________ of the impact on diagnostics, therapeutics and vaccines. The framework will serve as a guide for manufacturers and countries on changes (30) __________ may be needed for COVID-19 vaccines.