打完疫苗竟又確診?「突破性感染」大解密!|What is a COVID-19 vaccine ‘breakthrough’ case?

What is a COVID-19 vaccine “breakthrough” case? (AP Illustration/Peter Hamlin)

【看CP學英文】 究竟什麼是「突破性感染」?所謂「突破性感染」是指施打疫苗14天後仍遭受感染的狀況。不過針對新型冠狀病毒,這種病例很罕見,也是在預料之中,而美國醫療專家也表示無須因此感到驚慌。

What is a COVID-19 vaccine “breakthrough” case? It’s when a fully vaccinated person gets infected with the coronavirus. A small number of such cases are expected and U.S. health officials say they’re not a cause for alarm.

新冠疫苗理應要教會身體去辨認病毒,因此照理來說,如果在打完疫苗後接觸到病毒,身體的免疫系統應該有所反應,準備對抗病毒。

COVID-19 vaccines work by teaching the body to recognize the virus. So if you’re exposed to it after vaccination, your immune system should be ready to spring into action and fight it.

研究顯示,輝瑞(Pfizer)和莫德納 (Moderna) 的兩劑疫苗在預防感染新冠病毒上具有95%的效率,而只施打一劑的嬌生疫苗(Johnson & Johnson)則具有72%的效率。然而要在這三種疫苗之間做直接的比較仍有困難。新冠疫苗在預防感染病毒一事上固然表現良好,但在打完疫苗後染疫並不是完全不可能的,有些人根本不會出現症狀,有些人則會出現輕微症狀,甚至會生病。

In studies, the two-dose COVID-19 vaccines by Pfizer and Moderna were around 95% effective at preventing illness, while the one-shot Johnson & Johnson shot was 72% effective, though direct comparisons are difficult. So while the vaccines are very good at protecting us from the virus, it’s still possible to get infected with mild or no symptoms, or even to get sick.

據專家表示,若不幸在接種疫苗後確診了,疫苗會發揮功效,減輕重症機率,這才是大家應該去打疫苗的最大原因。

If you do end up getting sick despite vaccination, experts say the shots are very good at reducing the severity of the illness — the main reason to get vaccinated.

來自約翰斯·霍普金斯大學彭博公共衛生學院 (Johns Hopkins Bloomberg School of Public Health)的疫苗專家威廉・莫斯(Dr. William Moss)表示,大部分突破性感染者都僅會稍感不適。

Most people with breakthrough infections experience mild illness, said Dr. William Moss, a vaccine expert at the Johns Hopkins Bloomberg School of Public Health.

美國的新冠病毒住院及死亡人口當中,絕大部分都未接種過疫苗。

In the U.S., people who weren’t vaccinated make up nearly all hospitalizations and deaths from COVID-19.

其實要判斷突破性感染病例發生的原因並不容易,但莫斯表示,有可能是跟所接觸到的病毒量有關。此外,疫苗對身體有多適用也須看個人的免疫系統。有些人本身就患有疾病,或是在服藥當中,他們的免疫系統可能不會對疫苗產生太大的反應。

It’s difficult to determine why any particular breakthrough case happens. How much of the virus you’re exposed to could be a factor, Moss said. Our individual immune systems will also affect how well we respond to the shots. Some people, for example, have health conditions or take medications that could make their immune systems less responsive to the vaccines.

亦或者,突破性感染者有可能在疫苗還來不及完全發揮功效之前就接觸到病毒。莫斯也點出,病患接種到的疫苗有可能在接種前就存放不當,或是在疫苗施打過程中出現差錯,但這些情況的可能性都較低。

People might also have been exposed to the virus before the shots took full effect. Though less likely, they may have received a dose that was improperly stored or administered, Moss said.

美國疾病管制與預防中心(Centers for Disease Control and Prevntion)指出,有些突破性感染病例有可能是變種病毒所導致的,但就目前研究顯示,美國採用的疫苗都能有效對抗變種病毒。

The Centers for Disease Control and Prevention notes variants could be factors in some breakthrough cases, though evidence so far indicates the vaccines used in the U.S. are protective against them.

突發性感染病例若有上升趨勢,可能意味著疫苗的效力有待加強,或許是時候要求追加第三劑(booster)了。但突破性感染病例是否真的有上升趨勢,醫療專家仍在密切關注。

Health officials are also watching for signs that breakthrough cases are rising, which could signal that protection from the vaccines is fading and boosters are needed.