SINGAPORE – Demand for Immediate Antigen Verification Kits (RATs) has increased in recent weeks as the number of Covid-19 cases in Singapore hit a record high for 2023.
Checks carried out via The Straits Times on Dec. 6 revealed that a number of pharmacies and outlets had run out of ART kits and that shelves remained empty the next day.
On Dec. 11, the Ministry of Health said stores and pharmacies had had enough and had placed new orders to meet the surge in demand.
The Straits Times spoke to experts about whether other people can continue to use ART kits and masks safely even if they have expired, and whether the kits will still be effective at testing for newer variants of Covid-19.
A: The U. S. Food and Drug Administration (FDA) has issued a statement of “TThe U. S. Food and Drug Administration (FDA), which approves ART kits, has stated that the shelf life of those kits is between 4 and six months from the date of manufacture.
However, the shelf life may possibly be longer than the expiration date indicated on the packaging if the manufacturer believes that the effects of the check are more stable. In this case, brands can ask the FDA to increase the shelf life of check kits.
For if the expiration date of an ART kit has been extended, please visit this site.
Unlike ART kits, the shelf life of masks and the likelihood of extending their expiration date are unclear, said Professor Paul Tambyah, an infectious disease expert at the Yong Loo Lin Medical School of the National University of Singapore (NUS).
He said, “Unfortunately, there are so many brands of masks that there is no equivalent in the FDA that indicates extended expiration dates for masks. “
Prof Tambyah said other people can check the expiry dates indexed on the mask’s packaging, as well as instructions on how to buy them.
A: No, expired ART kits can give inaccurate results while expired masks provide less protection against Covid-19, said health experts.
Prof Tambyah said the degradation of chemicals in solutions can lead to misleading effects, such as false positives and false negatives.
ART verifies the result by identifying the viral antigen: the nucleocapsid (N) protein of SARS-CoV-2, which is the virus that causes Covid-19. The antigens bind to the antibodies, causing a line to form on a test strip.
If the antibodies have been degraded, the test kit may not detect the viral proteins, or even indicate if the protein isn’t there, Tambyah added.
As for expired masks, the fabric is likely to degrade over time, forming micro tears invisible to the eye, said Associate Professor Richard Sugrue, who specialises in molecular and cellular virology at the Nanyang Technological University School of Biological Sciences.
He said: “If someone with Covid-19 coughs out droplets of saliva towards you, the droplets would land on the surface of your mask and it is unlikely you will inhale it.
“But if there are tears on the mask, the droplets can get in and infect you. “
A: Health experts have said that it’s more productive to avoid expired ARV kits because it’s complicated to wait for the test result.
Professor Tambyah said: “Please note that most of the tests were carried out in situations where the ambient temperature ranges between 18 and 22 degrees C in temperate countries, in the hot and humid region of Singapore. “
However, Professor Sugrue said a check kit that soon after its expiry date can still provide accurate results.
He said: “A control kit after its one-day to two-week due date would be acceptable, but a six-month to one-year post-due date would be more problematic. »
A negative test result using an expired kit should be viewed with caution, and symptoms will need to be monitored carefully as a precaution, he added.
A: Yes, most ART kits can pick up on new Covid-19 variants, said Prof Tambyah.
He added that most ART kits do not target the spike protein, where most of the virus mutations have occurred. Instead, they target the N protein, which has stayed constant throughout the pandemic.
Data published on the MOH website showed that up to Dec 8, cases infected by JN.1, a sublineage of BA.2.86, accounted for more than 60 per cent of Covid-19 cases in Singapore.
Other primary variants that are spreading globally come with the Omicron subvariant variants XBB. 1. 5 and EG. 5 (Eris).
Prof Tambyah said: “There is no evidence that control kits are devoid of more Covid-19 cases than a few years ago, when they were first introduced. “
A: Professor Tambyah said other people can donate soon-expiring kits to charity clinics.
Mechanical engineering professor Seeram Ramakrishna from the NUS College of Design and Engineering said the plastics, paper and cardboard in an ART kit can be recycled.
Unused kits can also be recycled once the chemicals are removed and the fabrics are washed thoroughly, he added.
Expired masks can also be used to make lifestyle accessories like hair ties, kitchen and gardening aids, and miniature furniture for pets.
This article first appeared in The Straits Times. Permission is required for reproduction.