Should you go for COVID-19 antibody test after vaccination? Here’s what medical experts say

Allegations about people receiving “ghost jabs” during their COVID-19 inoculation have put some Malaysians on edge and spurred them to file complaints with the police and demand action against their vaccine administrators.

Some vaccine recipients who feel they may have been cheated are resorting to a COVID-19 Neutralising Antibody Test at a licensed medical laboratory 30 days after their second dose injection to confirm the presence of antibodies in their body. 

Several medical laboratories are now promoting such tests. Among them is Pathlab, which charges RM120 to check one’s COVID-19 antibody levels. 

Malay Mail spoke to two medical experts to find out their views on this topic and both agreed that these COVID-19 antibody tests should not be encouraged for several reasons. 

Dr Raj Kumar Maharajah, president of the Medical Practitioners Coalition Association of Malaysia, explained that results from COVID-19 antibody tests should not be used to evaluate a person’s level of immunity as there is still not enough research to support this. 

“When we talk about the value of antibody testing, it becomes very important to know whether the person was exposed in the past. Exposure through an infection will result in us having an adaptive immune response to the infection where antibodies are formed. 

“However it may not be so, post-vaccination. Studies are ongoing,” he told Malay Mail. 

He added that these antibody tests are not validated to evaluate immunity or protection from COVID-19 infection. 

He also said that these antibody tests should be ordered only by healthcare providers who are familiar with the use and limitations of the test and not directly by laboratories without the supervision of doctors.

“The risks that come with this is the false sense that one is protected and the attempt by unscrupulous people trying to rake monetary benefits from vulnerable sections of the public,” he said. 

His reasoning is supported by the US Food and Drug Administration (US FDA). 

In an article, the US FDA explained that authorised COVID-19 antibody tests have not been evaluated to assess the level of protection provided by an immune response to COVID-19 vaccination. 

It added that if antibody test results are interpreted incorrectly, there is a potential risk that people may take fewer precautions against COVID-19 exposure, which may result in the increased spread of COVID-19.

Dr Khoo Yoong Khean, a healthcare administrator working in Singapore and the managing editor of the Malaysian Medical Gazette, shared similar concerns.

He advised Malaysians to know fully what antibody testing is all about before engaging in such services as there is a risk that the results may be wrongly interpreted. 

“The body produces many antibodies at any given time, in the context of COVID-19, the main antibodies produced are against the nucleocapsid proteins (N) and spike proteins (S). In a natural COVID-19 infection, both N and S antibodies are produced. But in a vaccine (mostly mRNA) immune response, only the S antibody will be produced. 

“Therefore, if these tests in the market do not specify what type of antibodies it tests, or it doesn’t have someone with the knowledge to interpret correctly, many might falsely interpret them,” he explained.

Dr Khoo said that he would not encourage the public to go for an antibody test just to check the efficacy of the COVID-19 vaccine.

He said the immune response is a complicated mechanism and antibody levels are only a small part of the overall process. 

“Antibodies naturally fall in time, since we don’t need them if we are not infected but the body remembers how to produce them when needed, this is the ultimate aim of the vaccine. 

“Antibody tests also come with a lot of caveats; timing (days) of the tests, type of antibodies, person’s clinical condition and medical history. To use them widely as a public health testing measure would not be advisable,” he explained.

Sharing Dr Raj’s view, Dr Khoo added that these tests could cause people to be careless and neglect proven public health measures like wearing face masks properly, physical distancing and personal hygiene.

“In an example, if we do not detect N antibodies in a vaccinated person, it doesn’t mean he/she isn’t protected, or the presence of any antibodies is also not indicative of how ‘strong’ the protection are, simply because the levels fluctuate and dip after a while.

“If we were to rely on positive N antibodies only but not knowing what the levels are, it could give a false sense of security and people might unwisely abandon other proven public health,” Dr Khoo said. — Malay Mail