Home Health News Explainer: COVID-19 vaccine shots add to confusion over China’s tests for travelers

Explainer: COVID-19 vaccine shots add to confusion over China’s tests for travelers

8 min read

BEIJING (Reuters) – A coronavirus antibody take a look at that China has made necessary for arriving travelers has provoked considerations over its effectiveness after certainly one of a workforce of worldwide health consultants was briefly denied entry final week following a constructive consequence.

FILE PHOTO: People fill types earlier than receiving a dose of a coronavirus illness (COVID-19) vaccine at a vaccination web site, throughout a government-organized go to, in Beijing, China January 15, 2021. REUTERS/Carlos Garcia Rawlins

Although the British skilled from the World Health Organization (WHO) subsequently examined adverse, it was not instantly clear if the sooner consequence was a false constructive, or the results of earlier an infection or a COVID-19 vaccination.

Here are particulars of China’s testing guidelines, potential issues with the coverage, its implications for vaccinated people and consultants’ views.


Travellers from many nations, resembling Canada, Germany, Singapore and the United States, should present adverse outcomes of nucleic acid and Immunoglobulin M (IgM) antibody tests taken inside 48 hours of boarding.

China makes use of IgM antibodies, usually detected early in infections, as a supplementary device to filter out those that might have been contaminated however get a adverse consequence on nucleic acid tests.

However, some instances confirmed IgM antibodies can persist for an extended time, and even after practically full restoration.


It is feasible, however not at all times, consultants say. Most vaccines goal the “spike” protein on the virus floor to set off an immune response that would embrace IgM antibodies.

“We can assume that any COVID-19 vaccine containing the spike protein will induce IgM and therefore a diagnostic assay designed to detect spike specific IgM will not be able to differentiate vaccination from infection,” mentioned Helen Fletcher, a professor of immunology on the London School of Hygiene & Tropical Medicine.

Published information on Oxford University/AstraZeneca Plc’s COVID-19 vaccine exhibits spike protein-triggered IgM is detectable in some individuals at the very least 56 days after immunisation, Fletcher mentioned.


Tests to detect antibodies triggered by non-spike protein can yield adverse outcomes for those that bought vaccines concentrating on spike protein, mentioned Jin Dong-Yan, a professor of virology on the University of Hong Kong.

Vaccines concentrating on spike protein embrace these from AstraZeneca, Pfizer Inc and its accomplice BioNTech, and Moderna.


Such tests, nonetheless, may be problematic for different kinds of vaccines, together with complete virus-based shots that a number of Chinese builders use, some consultants mentioned.

“Where a person is injected with whole virus-based inactivated COVID-19 vaccine…there’s a strong chance that the person may also have positive result from non-spike protein IgM antibody tests,” mentioned Ian Jones, a virologist at Britain’s University of Reading.

China’s health authority doesn’t make clear whether or not its take a look at is designed to detect antibodies triggered by spike protein or different protein. The National Health Commission didn’t reply to a request for remark.


China doesn’t say clearly the way it decides to exempt vaccinated individuals from its necessities for adverse antibody tests.

Responding to a question on the subject, certainly one of its Singapore embassy employees mentioned a vaccinated foreigner can submit an immunisation certificates and await a response. China’s Foreign Ministry declined to remark.


At November’s G20 summit, Chinese President Xi Jinping proposed a worldwide mechanism for mutual recognition of health certificates, together with nucleic acid tests.

Experts hope China will think about using a vaccine passport to substitute the antibody take a look at.

“A vaccine passport will make travel to China much less of a hassle,” mentioned Huang Yanzhong, a health skilled at U.S. assume tank the Council on Foreign Relations.

“As Western countries achieve herd immunity through mass vaccination, they will start to open their borders… If China continues to have such strict test requirement, its airline, hotel and tourism industries will lose out.”

The WHO stays cautious: It refrained final week from advising that world journey be conditional on such proof, citing “critical unknowns” about how successfully the tests restrict unfold and in addition their restricted availability.

Reporting by Roxanne Liu and; Yew Lun Tian in Beijing; Editing by Miyoung Kim and Clarence Fernandez

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