世界杯滚球平台

每年的Covid助推器应该像流感疫苗一样

An yearly jab ahead of winter could become as routine as treating the flu. For the world to live alongside Covid-19 and to protect the most vulnerable, 这是最明智的选择.

一名年轻女子正在接受疫苗注射

Neil Mabbot教授, 罗斯林研究所免疫病理学的个人主席

By now more than 70 per cent of the UK population have received a third Covid vaccination, 或者是助推器. Many people who are older or at higher risk from Covid have had a fourth or even a fifth dose. But for how long and how often can we expect to continue to get Covid boosters? An annual booster, as we have with flu, could be a worthwhile precaution moving forward.

Covid vaccines have played a crucial role in protecting people against serious illness, 因感染SARS-CoV-2而住院和死亡, 导致Covid-19的病毒. However, vaccine immunity, particularly against infection, begins to wane after a few months.

Fortunately, booster vaccines effectively top up our immunity against SARS-CoV-2. 和最初的剂量一样, the protection boosters afford against serious outcomes is longer-lasting than against infection. 但这也是有限的.

By four months after a third dose of an mRNA vaccine, protection against omicron begins to wane. 一项研究表明,第四次注射后, 对感染的保护在四周达到顶峰, 之后开始逐渐下降.

Recent data has shown an increase in Covid infections in England and Wales, which is likely in part because vaccine immunity is beginning to wane for many people who had their third dose some months ago.

谁应该在什么时候注射?

Throughout the pandemic we’ve seen that older people and those with certain underlying health issues, 等, 患严重疾病的风险增加了吗, 因Covid住院和死亡.

So should we just give boosters to the most vulnerable every four months or so to help counteract the gradual decline in immunity? 或者间隔更长的时间也同样有效?

美国官员最近暗示了这一点, 展望未来, 大多数美国人可能每年只注射一次Covid疫苗. 而对感染的免疫力可能在今年早些时候减弱, this could be a practical compromise to ensure as many as possible are protected against serious illness and hospitalisation ahead of the winter.

But the incidence of serious illness and death in young people has been much less, 那么,他们真的也需要每年的助推器吗? A Swiss modelling study concluded that boosting only the most vulnerable groups isn’t likely to alleviate the impact of Covid on health systems. 在某种程度上, this is because Covid vaccination doesn’t only protect the person being vaccinated, but indirectly protects others as well by reducing onward spread of the disease.

作者提出, 同时优先考虑最脆弱的群体, boosting most of the population each year three to four months ahead of the winter peak is likely to be the best way to reduce infections and hospital admissions.

老先生展示他的疫苗膏药

世界杯滚球平台应该用什么疫苗?

Until recently most of the approved Covid vaccines have targeted the spike protein on the surface of the original strain of SARS-CoV-2. But some variants have mutations in their spike proteins that help them to evade the immunity gained from previous infection or vaccination.

为了抵消这一点, updated Covid vaccines that include the spike protein from the omicron variant are now being administered in some countries around the world, 包括英国的弱势群体. These “bivalent” vaccines are designed to offer a broader level of protection against Covid variants than that provided by the original vaccines.

But future variants might contain mutations that enable the virus to dodge the immunity even from these updated vaccines. 预测下一个变异是非常困难的.

鉴于这种, scientists are looking at different vaccine formats to future-proof Covid vaccines against a wider range of variants, 避免需要定期更新.

One candidate comprises nanoparticles that contain fragments of spike proteins from SARS-CoV-2 and seven other closely related viruses. In animal studies this vaccine provided good protection against infection with different coronaviruses.

Vaccines that train our T cells to recognise components of the SARS-CoV-2 virus other than the spike protein might also offer wider protection against future variants.

与此同时, 因为SARS-CoV-2感染呼吸道, administering the vaccine via a drop or spray to the mouth or nose could help train the mucosal immune system that lines the respiratory tract to recognise and kill the virus at its point of entry.

Many mucosal vaccines are in development and two are approved for use in China and India. 动物研究表明,这种方法有可能阻止感染, 这就是所谓的消毒免疫. However, these studies are preprints, meaning they’re yet to be peer-reviewed. 世界杯滚球平台还需要在人类身上看到同样的结果.

一年一次

Covid vaccines remain the most effective and safest way to protect against serious illness and death from the virus.

Reports on social media have suggested that repeated vaccination burns out your immune system, 但事实并非如此. Annual flu shots have been offered for decades with no evidence that this negatively affects immunity.

For some in the highest-risk groups, a more frequent booster may be required. 但对大多数人来说,每年注射新冠病毒疫苗似乎是一种明智的前进方式. 时间定在冬季临近, 这将有助于保护最脆弱的人免受严重疾病和死亡, 并减少这种疾病对世界杯滚球平台卫生系统的压力.

 

本文于2022年10月24日首次发表在The Conversation上.

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Picture credits: woman vaccinated - SolStock/Getty; elderly man - Juanmonino/Getty