疫苗激勵措施不會適得其反——政策制定者注意到了

精心設計的研究可以消除為疫苗提供現金會削弱信任的懷疑，並幫助醫療保健提供者設計有效的免疫接種活動。

2023 年 1 月 11 日 / 社論 / NATUIRE

 

瑞典的一項試驗顯示，如果給人們 200 克朗（24 美元）接種 COVID-19 疫苗，接種率會略有上升。

圖片來源：Karol Serewis/SOPA Images/LightRocket/Getty

 

2021 年年中左右，世界上一些政府開始創造性地實施 COVID-19 疫苗接種計畫。 為了讓盡可能多的人接種疫苗，他們開始提供不同尋常的激勵措施：在菲律賓聖路易斯，接種疫苗的居民可以參加抽獎活動，贏取一頭牛； 在香港，意外之財是一套公寓； 在西弗吉尼亞州，它是一把獵槍，還有其他獎品。

有關此類努力有效性的證據好壞參半，已完成的研究顯示，有保證的即時付款比噱頭和彩票更有效。 例如，2021 年在瑞典進行的一項隨機試驗顯示，向接受第一劑 COVID-19 疫苗的人支付 200 克朗（24 美元）的現金就足以將疫苗接種率提高 4.2 個百分點。

 

閱讀論文：疫苗接種的經濟激勵不會產生意想不到的負面後果

 

然而，人們和政策制定者仍然擔心此類激勵措施可能會產生意想不到的負面後果。 例如，人們可能期望未來的疫苗接種時亦有費用可拿。 或者他們可能認為付款是對不安全或可能令人不快的事情的補償。 現在，1 月 11 日發表在《自然》雜誌上的一篇論文中的兩項試驗的結果顯示，簡單的現金支付不會產生這種意想不到的影響。 研究團隊採取了設計研究的重要步驟來檢驗虛無假設。 這使他們具有統計能力來檢測是否存在影響，而不僅僅是記錄對負面後果上缺乏證據。 此類研究（包括測試無效結果）增加了圍繞疫苗接種經濟激勵的討論，並強調了對政策相關問題進行強有力研究的價值。

長期以來，經濟激勵和抑制措施一直被用來實現公共衛生目標，但一般來說，它們主要針對的是不健康的行為。 例如，對香煙徵稅以阻止吸煙。 隨機試驗顯示，直接現金支付可以有效地在懷孕期間戒菸。

但長期以來，人們一直擔心為疫苗接種付費可能會降低人們對疫苗安全性的信任，削弱他們的利他主義意識，並使未來的疫苗接種計畫難以在不付費的情況下實施。 儘管這些擔憂主要是理論上的，但它們已導致一些政策顧問建議不要實施提供現金以促進健康行為的計畫。 來自歐洲和美國的經濟學家團隊《自然》論文的作者，透過分析來自參與瑞典現金激勵計畫的 2,700 多人和美國 3,000 人的隨機研究數據，直接解決了這些擔憂 .

COVID 疫苗如何在八張強有力的圖表中塑造 2021 年

 

 

除了收集有關第二劑疫苗接種量的數據外，瑞典的研究還調查了人們對疫苗和其他健康行為的態度。 美國的研究考察了告知參與者為 COVID-19 疫苗提供公共資金的激勵計畫的存在是否會影響他們對產品安全性或有效性的看法、他們的公民責任感或他們接種流感疫苗或獻血的意願 . 總體而言，這些參數中的任何一個都沒有差異。 參與者也沒有報告說他們感到受到激勵措施的脅迫。

沒有任何一個實驗可以完全回答有關意外後果的問題，而且與其他任何研究一樣，這項研究也有其注意事項。 道德要求上要求所有參與者都知道他們是實驗的一部分，並且這種知識可能會影響他們對調查問題的回答。 結果也可能不適用於其他國家或其他疫苗：COVID-19 大流行在其突出性和政治化方面是獨一無二的，而且所研究的兩個地區都是高收入的西方國家。 這項研究也沒有解決更廣泛和更基本的倫理問題，這些倫理問題圍繞著花錢讓人們接種疫苗。

儘管結果支持這樣一種觀點，即可以在沒有意外負面後果的情況下部署貨幣激勵措施，但它們並不表明在資源不足的情況下應優先採用此類方法而不是改善疫苗的可及性。 努力建立信任或使人們更容易接種疫苗——例如，透過將有關接種的信息翻譯成不同的語言，或使疫苗接種中心更接近最需要的人群——是提高疫苗接種率的行之有效的方法，並且， 在某些情況下，成本可能低於提供經濟獎勵。

但是對於擁有資源來加強訪問和提供激勵措施的社區來說，最新的工作帶來了重要的數據和嚴格的方法來進行討論，該討論受到關於假設性負面後果的未經檢驗的假設的嚴重影響。 需要對政策相關問題的有效方法進行更多此類研究。 就疫苗而言，此類信息可用於幫助醫療保健提供者設計替代方法來促進疫苗接種——在另一場大流行再次來臨之前吸引政府走在科學前面並變得富有創造力。

 

自然 613, 215 (2023) ； doi: https://doi.org/10.1038/d41586-023-00018-z

參考文獻：

1.Thirumurthy, H., Milkman, K. L., Volpp, K. G., Buttenheim, A. M. & Pope, D. G. et al. PLoS ONE 17, e0263425 (2022).

2.Brewer, N. T. et al. Lancet Reg. Health Am. 8, 100205 (2022).

3.Campos-Mercade, P. et al. Science 374, 879–882 (2021).

4.Schneider, F. H. et al. Nature https://doi.org/10.1038/s41586-022-05512-4 (2023).

5.Berlin, I. et al. BMJ 375, e065217 (2021).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Vaccine incentives do not backfire — policymakers take note

Rigorously designed studies can dispel suspicions that offering cash for vaccines erodes trust, and help health-care providers to design effective immunization campaigns.

11 January 2023 / EDITORIAL / NATURE

 

A trial in Sweden showed that uptake rates rose slightly if people were given 200 krona (US$24) to have a COVID-19 vaccine.Credit: Karol Serewis/SOPA Images/LightRocket/Getty

 

Around the middle of 2021, some governments around the world began to get creative with their COVID-19 vaccination programmes. Eager to get vaccines into as many arms as possible, they began to offer unusual incentives: in San Luis, Philippines, vaccinated residents could enter a sweepstake to win a cow; in Hong Kong, the windfall was an apartment; in West Virginia, it was a hunting rifle, among other prizes.

Evidence about the effectiveness of such efforts is mixed1, and the research that has been done suggests that guaranteed, immediate payments are more effective than gimmicks and lotteries2. A randomized trial in Sweden in 2021, for example, showed that a cash payment of 200 krona (US$24) to those receiving their first dose of a COVID-19 vaccine was enough to drive up vaccination rates by 4.2 percentage points3.

 

Read the paper: Financial incentives for vaccination do not have negative unintended consequences

 

However, people and policymakers still worry that such incentives could have unintended negative consequences. People might expect payment for future vaccinations, for instance. Or they might think the payments are compensation for something that isn’t safe or could be unpleasant. Now, the results of two trials published in a paper on 11 January in Nature suggest that simple cash payments have no such unintended effects. The research team took the important step of designing the studies to test a null hypothesis. This gave them the statistical power to detect the absence of an effect, and not just document a lack of evidence for negative consequences. Such studies (including testing a null result) add to the discussion around financial incentives for vaccination and highlight the value of strong research for policy-relevant questions.

Financial incentives — and disincentives — have long been used to achieve public-health goals, but as a general rule, they have targeted mostly unhealthy behaviours. Take, for example, taxes on cigarettes to discourage smoking. Randomized trials indicate that direct cash payments can be effective in stopping smoking during pregnancy.

But there’s been a long-standing worry that offering payments for vaccination could reduce people’s trust in the safety of vaccines, erode their sense of altruism and make it difficult to implement future vaccine programmes without payments. Although these concerns are largely theoretical, they have led some policy advisers to recommend against implementing programmes that offer cash to promote healthy behaviours. The authors of the Nature paper, a team of economists from Europe and the United States, address such concerns head on by analysing data from randomized studies of more than 2,700 people involved in the Swedish cash-incentive programme and of 3,000 people in the United States.

 

How COVID vaccines shaped 2021 in eight powerful charts

 

As well as gathering data on second-dose uptake, the Swedish study also surveyed attitudes towards vaccines and other health behaviours. The US study looked at whether informing participants about the existence of incentive programmes that offer public funds for COVID-19 vaccines affected their perception of the products’ safety or efficacy, their sense of civic responsibility or their intention to get an influenza shot or donate blood. Overall, there was no difference in any of these parameters. Nor did participants report feeling coerced by the incentives.

No single experiment can completely answer questions about unintended consequences, and this study, like any other, has its caveats. Ethical requirements dictated that all participants knew they were part of an experiment, and it is possible that this knowledge coloured their responses to survey questions. The results also might not apply to other countries or other vaccines: the COVID-19 pandemic is unique in its pre-eminence as well as its politicization, and both regions studied are high-income, Western countries. Nor does this study address wider and more fundamental ethical questions around paying people to get vaccines.

And although the results support the idea that monetary incentives can be deployed without unintended negative consequences, they do not suggest that such approaches should be prioritized over improving access to vaccines when there are insufficient resources to do both. Efforts to build trust or make it easier for people to receive vaccines — by translating information about inoculations into different languages, for example, or bringing vaccination centres closer to the populations most in need — are well-established ways to boost vaccination rates and, in some cases, could cost less than offering financial rewards.

But for communities that have the resources to both bolster access and provide incentives, the latest work brings important data and a rigorous approach to a discussion that has been heavily influenced by untested assumptions about hypothetical negative consequences. More such studies are needed on effective approaches for policy-relevant questions. In the case of vaccines, such information can be harnessed to help health-care providers design alternative ways to promote vaccination — before another pandemic again entices governments to get ahead of the science and become creative.

Nature 613, 215 (2023)

doi: https://doi.org/10.1038/d41586-023-00018-z

References

6.Thirumurthy, H., Milkman, K. L., Volpp, K. G., Buttenheim, A. M. & Pope, D. G. et al. PLoS ONE 17, e0263425 (2022).

7.Brewer, N. T. et al. Lancet Reg. Health Am. 8, 100205 (2022).

8.Campos-Mercade, P. et al. Science 374, 879–882 (2021).

9.Schneider, F. H. et al. Nature https://doi.org/10.1038/s41586-022-05512-4 (2023).

10.Berlin, I. et al. BMJ 375, e065217 (2021).