COVID-19 疫苗：了解事实
想了解有关 COVID-19 疫苗的事实吗？以下是您需要了解的各种疫苗和接种疫苗的益处。
来自妙佑医疗国际员工
随着 2019 冠状病毒病（COVID-19）疫情持续蔓延，您可能会对 COVID-19 疫苗产生疑问。了解不同类型的 COVID-19 疫苗及其作用机制、潜在副作用，以及对您和家人的益处。
COVID-19 疫苗接种的好处
接种 COVID-19 疫苗有何益处？
及时接种最新 COVID-19 疫苗可以：
- 帮助预防儿童和成人中因 COVID-19 引起的严重疾病和死亡。
- 帮助避免因 COVID-19 而需要至医院就诊。
- 与感染导致 COVID-19 的病毒相比，这是一种更安全的自我保护方式。
- 增强身体的防护能力（也称为免疫力），防止感染导致 COVID-19 的病毒。
COVID-19 疫苗的保护程度取决于不同的因素。可影响疫苗保护程度的因素包括：年龄、既往是否曾患 COVID-19 或是否患有癌症等疾病。
COVID-19 疫苗的保护效果还取决于引起 COVID-19 的病毒如何变化，以及疫苗能针对哪些变异株。您的受保护程度还取决于时间，例如您接种疫苗的时间。
请向医疗护理团队咨询如何才能及时接种最新的 COVID-19 疫苗。
如果我已感染过 COVID-19，我是否还应接种 COVID-19 疫苗？
是的。在您患过 COVID-19 之后，接种疫苗可以增强您身体的防护能力，防止再次感染导致 COVID-19 的病毒。
接种 COVID-19 疫苗或接种 COVID-19 疫苗可提供保护，也称为免疫力，使您不会再次感染导致 COVID-19 的病毒。但随着时间的推移，这种保护效果会逐渐消失。再次感染 COVID-19 可能会导致严重疾病或医学并发症，尤其是对于存在 COVID-19 重症风险因素者。
研究人员在继续研究第二次感染 COVID-19 时会出现的情况。但有些人可能会发现，每感染一次 COVID-19，他们不得不去医院就诊，且出现糖尿病等医学问题的风险就会增加。
研究发现，患过 COVID-19 且接种了所有建议的 COVID-19 疫苗的人群，因 COVID-19 而住院治疗的可能性低于未接种疫苗或未接种所有建议疫苗的人群。这种保护作用会在接种疫苗后的几个月内逐渐消失。
此外，由于导致 COVID-19 的病毒会发生变化，也称为变异，因此接种正在传播或预计会传播的最新毒株或变异株的疫苗有助于防止再次患病。
COVID-19 疫苗的安全性和副作用
哪些 COVID-19 疫苗已获得授权或批准？
在 COVID-19 大流行之初，迫切需要 COVID-19 疫苗。美国食品药品管理局（FDA）的疫苗审批过程可能需要数年时间。
因此，FDA 根据比通常要求更少的数据而首次授权 COVID-19 疫苗的紧急使用。不过，数据仍然必须证明这些疫苗安全有效。
获得 FDA 紧急使用授权的疫苗包括：
辉瑞－生物科技 COVID-19 疫苗。该疫苗最先针对自2019 年底起传播并导致 COVID-19 的原始病毒株进行检测。2020 年 12 月，研究发现辉瑞－生物科技 COVID-19 疫苗的2 剂系列在预防 18 岁及以上人群感染 COVID-19 方面安全且有效性达 91% 至 95%。这些数据协助预测了疫苗对较年轻人群的效果。有效性因年龄而异。
辉瑞－生物科技疫苗（Comirnaty）已获批用于 12 岁及以上人群。该疫苗已获批用于 6 个月及以上人群。该疫苗系列的接种剂数取决于个人的年龄和 COVID-19 疫苗接种史。
2022 年 8 月，FDA 授权了对莫德纳和辉瑞－生物科技的 COVID-19 疫苗的更新。这两种疫苗目前均可预防导致 COVID-19 的原始病毒株和奥密克戎变异株。更新版二价疫苗在已接种最新的 COVID-19 疫苗的人群中仍可预防重症。一项分析表明，这些疫苗使患有 COVID-19 的成人患者避免住院治疗 COVID-19 的有效性高达 62%。
- 诺瓦瓦克斯 COVID-19 佐剂疫苗。该疫苗目前已获得用于 12 岁及以上人群的紧急使用许可。该疫苗需接种两剂，间隔 3 至 8 周。在德尔塔和奥密克戎变异株传播之前所完成的研究表明，该疫苗在预防 COVID-19 轻症、中症和重症方面的有效性为 90%。对于 65 岁及以上的人群，该疫苗的有效性为 79%。
COVID-19 疫苗如何发挥作用？
辉瑞－生物科技和莫德纳的 COVID-19 疫苗均使用基因工程信使 RNA（mRNA）。冠状病毒表面有一种名为 S 蛋白的刺突状结构。COVID-19 mRNA 疫苗可为细胞提供制造无害 S 蛋白片段的指令。
接种疫苗后，您的肌肉细胞开始制造 S 蛋白片段，并将其显示在细胞表面。免疫系统可以识别出这种蛋白质，并开始建立免疫反应和产生抗体。传递指令后，mRNA 会立即分解。其绝对不会进入保存 DNA 的细胞核中。
诺瓦瓦克斯 COVID-19 佐剂疫苗是一种蛋白亚单位疫苗。这一类疫苗仅包括最能刺激免疫系统的病毒部分（蛋白质）。诺瓦瓦克斯的 COVID-19 疫苗含有无害的 S 蛋白。该疫苗中还含有一种被称为佐剂的成分，有助于提高免疫系统的反应能力。
一旦免疫系统识别出 S 蛋白，该疫苗就会产生抗体和防御性白细胞。如果您之后感染了 COVID-19 病毒，这些抗体将对抗病毒。
蛋白亚基 COVID-19 疫苗不使用任何活病毒，不会导致感染 COVID-19 病毒。蛋白片段也不会进入保存 DNA 的细胞核中。
COVID-19 疫苗会让您感染 COVID-19 吗？
否。目前在美国研发和使用的 COVID-19 疫苗并未使用会导致 COVID-19 的活病毒。正因如此，COVID-19 疫苗不会导致您感染 COVID-19 或排出任何疫苗成分。
接种 COVID-19 疫苗后，身体需要几周时间才能产生免疫力。因此，在接种疫苗之前或之后的短时间内，您有可能感染导致 COVID-19 的病毒。
COVID-19 疫苗可能存在哪些一般副作用？
COVID-19 疫苗在第一或第二剂接种后可引起轻微副作用，包括：
- 注射部位疼痛、发红或肿胀。
- 发热。
- 疲劳。
- 头痛。
- 肌肉疼痛。
- 寒战。
- 关节疼痛。
- 恶心和呕吐。
- 感觉不适。
- 淋巴结肿大。
6 个月到 3 岁的宝宝在接种疫苗后也可能会哭闹、困倦或食欲不振。
医疗护理团队会在您接种 COVID-19 疫苗后进行 15 分钟的监测，以观察您是否出现过敏反应。
许多人在接种疫苗后不会出现副作用。大多数副作用会在几天内消失。
如果注射部位的发红或触痛在 24 小时后加剧，或您担心任何副作用，请联系医生。
COVID-19 疫苗有什么长期副作用？
由于 COVID-19 疫苗临床试验是在 2020 年夏季才开始，因此尚不清楚疫苗是否会引起长期副作用。然而，疫苗很少会引起长期副作用。
如果您担心，美国的COVID-19 疫苗安全性数据将被报告给“疫苗不良事件报告系统”的国家项目。该数据可供公众查阅。CDC 还创建了 v-safe（一种基于智能手机的工具），允许用户报告 COVID-19 疫苗的副作用。
如果您对自己的症状有其他问题或疑虑，请咨询医生。
COVID-19 疫苗可能会影响心脏吗？
在部分接种者中，COVID-19 疫苗可导致心肌炎和心包炎等心脏并发症。心肌炎是指心肌发生肿胀，也称为心脏肌肉炎症。心包炎是指心包发生肿胀，也称为心脏外包膜炎症。
虽然 mRNA COVID-19 疫苗接种后出现心肌炎和心包炎很罕见，但美国的报告病例有所增加，尤其是 12 至 39 岁的男性。研究还表明，接种诺瓦瓦克斯的 COVID-19 疫苗后出现这些病症的风险更高。
在患心肌炎或心包炎的报告病例中，更多是在接种第二剂 COVID-19 疫苗后患病，且通常发生在接种 COVID-19 疫苗后一周内。多数接受护理的患者在服药和休息后能够好转。
需要格外留意的症状包括：
- 胸部疼痛。
- 气短。
- 感觉心脏快速跳动、扑动或剧烈跳动。
如果您或您的孩子在接种 COVID-19 疫苗后一周内出现任何这些症状，请就医。
如果您或您的孩子在接种一剂 mRNA COVID-19 疫苗后出现心肌炎或心包炎，CDC 建议避免再次接种任何 COVID-19 疫苗。
变体和 COVID-19 疫苗
COVID-19 疫苗是免费的吗？
在美国，联邦政府向所有居民免费提供 COVID-19 疫苗，无论其移民身份或健康保险承保范围如何。COVID-19 疫苗由专科门诊、零售药房或其他地点免费提供。
如果我已有其他健康问题，可以接种 COVID-19 疫苗吗？
可以，COVID-19 疫苗对已存在其他健康问题的人群是安全的，包括患 COVID-19 严重疾病的风险较高的人群。
如果您属于中度或重度免疫系统低下人群，您的医疗护理团队可能会建议增加 COVID-19 疫苗的剂次。
CDC 建议，免疫系统功能低下的人群、65 岁及以上人群，以及其他因担心患重症风险而需要快速形成免疫保护的人群应以最短的间隔接种第一剂和第二剂 mRNA COVID-19 疫苗。对于某些人，尤其是 12 至 39 岁的男性，第一剂和第二剂之间最好间隔 8 周。间隔时间越长，对 COVID-19 的保护作用越强，患心肌炎和心包炎等罕见心脏问题的风险也越低。
接种 2019 冠状病毒病（COVID-19）疫苗前后是否可以服用非处方止痛药？
请勿在接种 COVID-19 疫苗前为了预防可能的不适而服药。尚不清楚这些药物可能对疫苗有效性产生什么影响。不过，只要没有其他医学原因禁止您服用这类药物，您在接种 COVID-19 疫苗后可以使用。
过敏反应和 COVID-19 疫苗
2019 冠状病毒病（COVID-19）疫苗过敏反应的体征有哪些？
如果您在接种疫苗后 4 小时内出现以下症状，则可能是对 COVID-19 疫苗产生了速发过敏反应：
如果您出现任何过敏反应体征，请立即就医。将您的反应告知医生，即使这种反应已自行消失或您没有接受急救护理。这种反应可能意味着您对疫苗过敏。您可能无法再接种同一疫苗的第二剂。不过，您可能可以在接种第二针时使用其他疫苗。
如果我有过敏反应史，可以接种 COVID-19 疫苗吗？
如果您有与疫苗或注射药物无关的严重过敏反应史，您仍然可以接种 COVID-19 疫苗。接种疫苗后，通常会对您进行 30 分钟的监测。
如果您对其他疫苗或注射药物会立即产生过敏反应，请向医生咨询接种 COVID-19 疫苗的事宜。如果您曾对某种 COVID-19 疫苗中的任何成分产生即时或严重过敏反应，CDC 建议您不要接种该疫苗。
如果您在接种第一剂 COVID-19 疫苗后出现即时或严重过敏反应，请不要再接种第二剂。不过，您可能可以在接种第二剂时使用其他疫苗。
COVID-19 疫苗对怀孕、母乳喂养和生育能力的影响
孕期或哺乳期女性能接种 COVID-19 疫苗吗？
如果您处于妊娠期或哺乳期，CDC 建议您接种 COVID-19 疫苗。
孕妇感染 COVID-19 的总体风险较低。但是，已怀孕或刚怀孕的女性患 COVID-19 重症的风险更高。患有 COVID-19 的孕妇也更有可能在妊娠第 37 周开始前就分娩（早产）。她们还可能面临更高的风险，如死产和妊娠丢失。
接种 COVID-19 疫苗可以使您免受 COVID-19 引起的严重疾病。接种疫苗还能帮助孕妇产生抗体，从而保护其婴儿。研究表明，如果产妇接种过两剂 mRNA COVID-19 疫苗（如辉瑞－生物科技或莫德纳的 COVID-19 疫苗），该产妇分娩的婴儿在出生后最初 6 个月内因 COVID-19 感染而住院治疗的风险可能较低。
COVID-19 疫苗不会导致孕妇或其分娩婴儿感染引起 COVID-19 的病毒。COVID-19 疫苗均不含导致 COVID-19 的活病毒。此外，请记住，mRNA COVID-19 疫苗不会改变您的 DNA。
一项对 4 万多名妇女进行的大型研究结果表明，在妊娠期接种 COVID-19 疫苗不会给接种的孕妇及其婴儿带来重大风险。研究中的大多数女性都接种了 mRNA 疫苗。
既然儿童感染 COVID-19 后极少出现严重疾病，为什么他们还需要接种 COVID-19 疫苗呢？
虽然很少见，但一些儿童在感染引起 COVID-19 的病毒后，可能会患上重症 COVID-19。
COVID-19 疫苗和加强针（针对最常见的 COVID-19 病毒株进行了更新）可能有助于防止您的孩子感染 COVID-19 病毒。该疫苗和加强针还可以防止您的孩子因感染 COVID-19 病毒而患重病或不得不住院。
接种 COVID-19 疫苗后，我可以停止采取安全防护措施吗？
如果您已在符合条件时接种了推荐的所有 COVID-19 疫苗，即被视为及时接种了最新疫苗。
接种疫苗后，您就可以更安全地重新开始之前因疫情而无法进行的活动。但如果您所在的地区有大量 COVID-19 住院病例，CDC 建议在室内公共场合佩戴合适的口罩，无论您是否已接种疫苗。
如果您的免疫系统功能低下或患重症的风险较高，当您所在地区有大量 COVID-19 住院病例时，请佩戴最具防护性的口罩。对于其他时间是否应该佩戴口罩，请咨询医务人员。
CDC 建议您在乘坐飞机、公共汽车、火车和其他公共交通工具前往美国、在美国境内往来或离开美国时，以及在机场和火车站等场所佩戴口罩。
如果您已经接种了所有推荐剂次的疫苗，但与携带 COVID-19 病毒者有过密切接触，请在接触后进行检测，至少持续 5 天。
接种疫苗后，我还会感染 COVID-19 吗？
接种
COVID-19 疫苗可保护大多数人免于感染 COVID-19。但一些全程接种疫苗者仍会感染 COVID-19。这种现象被称为疫苗突破性感染。
疫苗突破性感染者可将 COVID-19 传播给他人。不过，与未接种疫苗者相比，全程接种疫苗的突破性感染者患上重症 COVID-19 的可能性较低。即使接种疫苗者出现症状，其严重程度也往往低于未接种疫苗者。
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