【文／Siddharth Sridhar 薛達；香港大學微生物學系臨床助理教授】

（編按：薛達撰文指出，香港的武漢肺炎 (COVID-19) 疫苗接種率偏低，主要與「疫苗猶豫 (vaccine hesitancy) 」有關，他全文以 8 點解釋這種等待更多人接種疫苗自己才打針的做法，會延遲香港達到群體免疫。文章標題為 "COVID-19 vaccines: what are you waiting for? "） 

One of the biggest problems slowing the COVID-19 vaccination drive in Hong Kong is the 'wait & see' policy of many people in the community. 'Wait & see' is a form of vaccine hesitancy where people are not exactly against the vaccine, but also do not overcome their inertia to get the jab. In the end, 'wait & see' is just as problematic as an anti-vaxxer movement because it means fewer shots-in-arms and delays herd immunity.

When people tell me they are waiting before receiving the vaccine, I ask them "What exactly are you waiting for?" The replies vary, but often involve concerns and questions to which we already have clear answers. So I would like to summarize some of my responses to these concerns/questions below.
Common reasons for 'wait & see':

1. "I don't think the vaccines are effective."

Response: Both vaccines available in Hong Kong prevent symptomatic COVID-19 and severe COVID-19. They have demonstrated this in both company-sponsored trials as well as independent post-marketing trials in countries where the vaccines have been launched. There is absolutely NO doubt that these vaccines work against COVID-19.

2. "I don't think the protection is long-lasting. So why bother getting it so early?"

Response: In a recent company press release, the efficacy of the BioNTech vaccine > 6 months after the second dose is still > 90%. The strength of the antibody response generated by mRNA vaccines indicates that protection up to an year or beyond should be no problem whatsoever. It is possible that some people may require periodic revaccination in subsequent years (especially if the virus changes significantly), but there is no doubt that protection is quite durable. Data on duration of protection of CoronaVac is still pending, but hopefully will be out later this year.

3. "What about all these variants? Don't they make vaccines useless?"

Response: In a nutshell, first generation vaccines are effective against variants. The B.1.1.7 (UK) variant has little to no effect on efficacy of vaccines. A recent press release indicates preliminary excellent efficacy of BioNTech in South Africa where B.1.351 predominates. Hearteningly, CoronaVac also seems to maintain efficacy in a recent study in Manaus, Brazil where the P.1 variant circulates. Furthermore, even if these variants impact efficacy against symptomatic disease, there is good reason to believe that they should still offer protection against severe COVID-19.

4. "Not sure if the vaccines are safe or not. I want more people to get them first to see what happens."

Response: No point doing this because MILLIONS of people around the world have already received BioNTech and CoronaVac with no worrisome safety signals. It is extremely unlikely that some rare vaccine side effect is going to emerge in Hong Kong and not in other places. I would like to reemphasize that it is impossible for either of these vaccines to change your DNA. There have been no shortcuts whatsoever on safety assessment of these vaccines.

5. "I don't think COVID-19 is a big deal. What's the point vaccinating against it?"

Response: COVID-19 has killed approximately 3 million people since it began. The mortality due to COVID-19 disproportionately affects elderly and those with chronic medical conditions. In Hong Kong, we have suffered extreme social disruption due to the virus and vaccination is the only way to consistently keep COVID-19 cases down. Even if you are a young person, receiving the vaccine almost eliminates risk of severe COVID-19 and also gives indirect protection to members of your household who have not received the vaccine. Therefore, getting the vaccine is the best thing you can do for yourself, your family, and your community. If you still need another incentive, it is a matter of time before travel bubbles contingent on vaccination are introduced in the region. At least in the short term, it is likely that overseas travel will require proof of vaccination. Remember that such travel bubbles can only happen if COVID-19 is kept down in HK and this requires high vaccination rates.

6. "I am waiting for a single shot vaccine."

Response: I have another post on why this is not a good idea. I cannot think of a good reason to wait for another vaccine to come to HK before getting the vaccine.

7. "I have chronic medical conditions. I don't think I am fit to get the vaccine."

Response: People with most chronic medical conditions can safely receive COVID-19 vaccines and indeed they are recommended to do so due to their higher underlying risk of severe COVID-19. As long as your condition is reasonably stable without recent changes in medications, you can go ahead and get the vaccine. Talk to your medical provider if you are still in doubt.

8. "If we still have to wear masks and observe social distancing, what is the point of vaccination?"

Response: It takes time to vaccinate enough people to achieve herd immunity. During this time, COVID-19 transmission can still occur and cause large outbreaks. This is why we still need to observe masking and social distancing rules while we wait for sufficient number of people to get vaccinated in the community. Once HK reaches herd immunity, we can certainly aim for a sustained relaxation of social distancing and masking measures.

These are some of the reasons for 'wait & see' that I can think of. Feel free to let me know of other concerns you might have encountered. 🙂

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