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与新冠病毒共存可能的后果:每年至少感染一次

与新冠病毒共存可能的后果:每年至少感染一次

Erin Prater 2022-05-30
病毒变异的速度超过了现有疫苗技术发展的速度,可能导致现有疫苗未来彻底失效。

新冠并不是“感染一次就能够免疫”的疾病。

药品开发商Fractal Therapeutics的模拟显示,未接种疫苗和不戴口罩的人可能一年左右感染一次新冠,未接种疫苗但在公共场合经常配戴“优质”口罩的人可能每两年感染一次新冠。

新冠研究人员、Fractal Therapeutics公司的首席执行官阿里吉特·查克拉瓦蒂表示,已经接种疫苗的人群,无论是否配戴口罩,预计感染新冠的“频率低得多”,尽管无法准确预测感染频率。

他说:“总之,如果你计划不戴口罩,像往常一样生活,那么你可能每年至少感染一次新冠。如果你计划在除家以外的其他地方都配戴口罩,就可以将感染风险降低一半。”

该团队的最新模型考虑到了疫苗和之前感染带来的免疫力逐渐下降的情况,以及一定程度的免疫逃逸。目前,奥密克戎亚变异株出现免疫逃逸的情况越来越多。团队还假设患者每一次感染,都能够临时获得对于有时会致命的新冠病毒某种程度的保护力。

查克拉瓦蒂称,其团队并未考虑到出现完全免疫逃逸的变异株的可能。

查克拉瓦蒂指出,模拟之所以以未接种疫苗者为重点,是因为对美国大多数人而言,尽管疫苗可以避免重症和死亡,但“目前并没有提供防止感染的保护力”。

美国接种过一剂加强针的人口比例很小,据美国疾病控制与预防中心(CDC)统计只有46.5%,而接种第二剂加强针的人口比例更是只有19.7%。他表示,无论如何,“加强针只能够提供防止感染的短期保护力。”疫苗和之前感染所产生的免疫力被认为会在三四个月后逐渐减弱,只是实际情况因人而异。

开发鼻喷疫苗的理由

查克拉瓦蒂的团队还模拟了疫苗依旧受到免疫逃逸的影响,但公众可以“一遍一遍使用”现有疫苗的情况。

他说:“我们假设每一轮接种疫苗能够使抗体滴度增加15倍,事实上,如果你频繁接种疫苗确实可以做到,就能够大幅降低感染的风险。”

他表示,这种假设“可能很值得在现实世界中进行测试。”虽然很少有人愿意每八周左右接种一剂疫苗,承受现有疫苗的副作用,但更多人可能愿意使用已经上市的鼻喷雾疫苗,因为这种疫苗的副作用更少。

病毒变异的速度超过了现有疫苗技术发展的速度,可能导致现有疫苗未来彻底失效。查克拉瓦蒂称,但“我们并没有充分探索”这种技术可以提供保护力的范围。

“除了开发能够更有效预防现有变异病毒株的疫苗以及鼻喷雾疫苗以外,这方面还需要进行更多的研究,探索接种疫苗的频率,以及通过频繁接种疫苗来增加中和抗体的效果。”

查克拉瓦蒂表示,这项研究可能不需要完整的临床试验,但首先可以分析中和抗体滴度,并思考一个问题:“哪一种疫苗剂量能够提供更高的抗体滴度,并且从安全性角度是可以接受的?”

“这方面研究的成本相对较低,即便在研究下一代疫苗的过程中,也能够带来收益。”他说。(财富中文网)

译者:刘进龙

审校:汪皓

新冠并不是“感染一次就能够免疫”的疾病。

药品开发商Fractal Therapeutics的模拟显示,未接种疫苗和不戴口罩的人可能一年左右感染一次新冠,未接种疫苗但在公共场合经常配戴“优质”口罩的人可能每两年感染一次新冠。

新冠研究人员、Fractal Therapeutics公司的首席执行官阿里吉特·查克拉瓦蒂表示,已经接种疫苗的人群,无论是否配戴口罩,预计感染新冠的“频率低得多”,尽管无法准确预测感染频率。

他说:“总之,如果你计划不戴口罩,像往常一样生活,那么你可能每年至少感染一次新冠。如果你计划在除家以外的其他地方都配戴口罩,就可以将感染风险降低一半。”

该团队的最新模型考虑到了疫苗和之前感染带来的免疫力逐渐下降的情况,以及一定程度的免疫逃逸。目前,奥密克戎亚变异株出现免疫逃逸的情况越来越多。团队还假设患者每一次感染,都能够临时获得对于有时会致命的新冠病毒某种程度的保护力。

查克拉瓦蒂称,其团队并未考虑到出现完全免疫逃逸的变异株的可能。

查克拉瓦蒂指出,模拟之所以以未接种疫苗者为重点,是因为对美国大多数人而言,尽管疫苗可以避免重症和死亡,但“目前并没有提供防止感染的保护力”。

美国接种过一剂加强针的人口比例很小,据美国疾病控制与预防中心(CDC)统计只有46.5%,而接种第二剂加强针的人口比例更是只有19.7%。他表示,无论如何,“加强针只能够提供防止感染的短期保护力。”疫苗和之前感染所产生的免疫力被认为会在三四个月后逐渐减弱,只是实际情况因人而异。

开发鼻喷疫苗的理由

查克拉瓦蒂的团队还模拟了疫苗依旧受到免疫逃逸的影响,但公众可以“一遍一遍使用”现有疫苗的情况。

他说:“我们假设每一轮接种疫苗能够使抗体滴度增加15倍,事实上,如果你频繁接种疫苗确实可以做到,就能够大幅降低感染的风险。”

他表示,这种假设“可能很值得在现实世界中进行测试。”虽然很少有人愿意每八周左右接种一剂疫苗,承受现有疫苗的副作用,但更多人可能愿意使用已经上市的鼻喷雾疫苗,因为这种疫苗的副作用更少。

病毒变异的速度超过了现有疫苗技术发展的速度,可能导致现有疫苗未来彻底失效。查克拉瓦蒂称,但“我们并没有充分探索”这种技术可以提供保护力的范围。

“除了开发能够更有效预防现有变异病毒株的疫苗以及鼻喷雾疫苗以外,这方面还需要进行更多的研究,探索接种疫苗的频率,以及通过频繁接种疫苗来增加中和抗体的效果。”

查克拉瓦蒂表示,这项研究可能不需要完整的临床试验,但首先可以分析中和抗体滴度,并思考一个问题:“哪一种疫苗剂量能够提供更高的抗体滴度,并且从安全性角度是可以接受的?”

“这方面研究的成本相对较低,即便在研究下一代疫苗的过程中,也能够带来收益。”他说。(财富中文网)

译者:刘进龙

审校:汪皓

COVID is not a "one and done" thing—far from it.

Those who are unvaccinated and don't mask can expect to come down with COVID once a year or so—once every other year for the unvaccinated who regularly use a "good quality" mask in public, according to modeling by drug developer Fractal Therapeutics.

As for the vaccinated, both masked and unmasked, they can expect to get COVID "a lot less frequently," though it's impossible to say just how often, said Arijit Chakravarty, a COVID researcher and Fractal Therapeutics CEO.

"The bottom line is if you are planning not to use a mask and live your life as usual, expect to get infected at least once a year, if not more," he said. "If you're planning to mask everywhere but at home, that probably cuts the risk in half."

The team's latest models accounts for waning immunity from vaccines and prior infection, and a certain degree of immune evasion, as has been increasingly seen in Omicron subvariants. It also assumes that with each round of infection, a person gains some measure of protection against the sometimes deadly virus, albeit temporary.

It does not account for the possible evolution of a variant that completely evades immunity, he cautioned.

The modeling focuses on the unvaccinated because "vaccines are not currently providing protection against infection" for the majority of the U.S. population, though they are providing protection against severe illness and death, Chakravarty said.

The percentage of Americans who've received one booster is small—46.5%, according to the CDC—and smaller yet for a second booster: 19.7%. Regardless, "boosters only provide a short duration of protection against infection," he said. Immunity, whether from vaccine or prior infection, is thought to wane after three or four months, though it varies by person.

The case for a nasal vaccine

Chakravarty's team also ran simulations in which the vaccine is still undermined by immune evasion, but the public is able to "dose over and over again" with current vaccines.

"If we assume that each new round of vaccine gives you a 15-fold jump in antibody titers—yes, in fact, if you vaccinate very often, you can probably massively reduce the risk of being infected," he said.

The hypothesis "might well be worth testing in the real world," he said. While few would want to deal with a jab and current vaccine side effects every eight weeks or so, more might be willing to take a readily available nasal-mist vaccine, which may cause fewer side effects.

Variants are outpacing current vaccine technology, potentially rendering it completely ineffective in the future. But "we haven't fully explored the range" of what that technology can provide in the way of protection, Chakravarty said—not yet.

"More research needs to be done on this—in addition to coming up with vaccines that work better against the current viral variants, vaccines that can be used nasally—exploring how often vaccines can be given, and how much of a boost to our neutralizing antibodies we could get from frequent administration.”

Such research might not require full clinical trials, but could start by looking at neutralizing antibody titers and asking the question, "What course of vaccine doses provide higher titers while still being acceptable from a safety standpoint?" Chakravarty said.

"It's a relatively low-cost thing to fund and could yield benefit, even as we're exploring next-generation vaccines."

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