People will probably need a Covid-19 vaccine annually to protect themselves from the virus, health authorities in the UAE said.
Although the virus does not mutate as quickly as the common flu, the emergence of variants that can evade antibodies suggests repeated vaccination may be required to fight different strains, experts said.
"The more mutant the virus, the more is the possible need to vaccinate annually against it," said Dr Farida Al Hosani, spokeswoman for the UAE's government health authorities, during an online panel discussion on Tuesday.
The flu vaccine, which protects against up to four strains, is administered with the same frequency, she said.
Vaccine manufacturers said tests show their shots still work against the variants, but their efficacy is reduced.
On Tuesday, Moderna said its Covid-19 vaccine can protect against two of the major strains identified in the UK and South Africa.
But the blood from people vaccinated with the company’s shot generated a sixfold reduction in the level of antibodies against the variants, suggesting an earlier waning of immunity against the newer strains.
The company said it does, however, still offer protection. It is testing whether a booster shot can improve immune responses to the variants. It will first tackle the South African strain.
Initial tests suggested the Sinopharm vaccine, which is widely available in the UAE, can also neutralise the virus variants, but its efficacy is also impaired.
"Preliminary lab results show that antibodies produced by Chinese inactivated Covid-19 vaccines can neutralise existing variants found in the UK and South Africa, although the efficacy is slightly weakened," said Shao Yiming, a scientist with the Chinese Centre for Disease Control and Prevention agency, in an interview with Global Times.
Scientists are now assessing the need to redesign the various inactivated vaccines produced in China, he said.
This week, Dr Al Hosani said people immunised against Covid-19 can still contract and spread the virus, so they must remain cautious.
Vaccinated people should still be rigorous in their handwashing, wear face masks and maintain physical distancing to protect themselves and others.
"Although the risk is less, there is still a risk that we should not underestimate," she told The National.