Letters | Hong Kong Covid vaccines: allow booster shots of different brand
- For people who have received vaccination but whose antibody blood test turns up negative, the authorities should allow the option of an alternative shot
Health authorities worldwide generally agree that a negative antibody test after Covid vaccination does not imply absence of immunity. There remains the possibility of unmeasured cellular memory immunity from B and T cells.
Local people with a negative response to one Covid vaccination course are currently prohibited by the government from making good by opting for booster jabs of the alternative vaccine. Presumably official government reasoning is to reserve vaccine stock to enable as many people as possible to receive their very first course of vaccine. However, persons with negative antibodies after vaccination remain a risk to themselves and the community at large.
The government is currently planning to reduce cross-border travel restrictions for people with negative Covid nucleic acid tests, coupled with positive antibody tests after vaccination. This implies our health authorities consider post-vaccination antibody tests as an indicator of presence or absence of immunity.
For people who have received Covid vaccination but whose post-vaccination antibody blood test turns up negative, the health authorities should at least allow the option of booster shots of an alternative vaccine.
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