Is a 4th dose of vaccine needed when Omicron is spreading strongly?
Health officials say the booster dose provides immunity against the Omicron variant, so they are considering a fourth dose.
However, some experts believe that may not be necessary when humans can eventually live with Covid-19.
Latest data from the UK shows that the third dose of the vaccine is effective againstOmicron.Up to 80% chance of preventing the disease from getting worse.
Dr Quinton Fivelman, of London Medical Laboratories, said Omicron's "success" could make another vaccine unnecessary.
Currently in South Africa, where Omicron was first detected, Mr. Fivelman noted that the new strain is less severe than Delta.
As it spreads rapidly, Omicron is wreaking havoc on itself. Antibodies from previous Omicron infections are effective against several other strains.
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| Illustration: Biovendor |
“Omicron has been able to spread so rapidly in South Africa that a large proportion of the unvaccinated population has been infected and recovered,” Dr Fivelman said.
"It appears that cases have peaked and are declining. Even better news is that the immune response of people who have been infected with Omicron appears to be four times more protective against Delta. That means Omicron is rapidly replacing the less infectious but more severe Delta strain."
Experts believe that, like all viruses, previous infection with Omicron confers natural immunity. However, Dr. Luis Ostrosky, head of the infectious disease division at the University of Texas Health Science Center (USA), said that antibodies begin to decline after a few months.
Infection with Omicron does not guarantee protection against future variants, Dr. Ostrosky predicts. Vaccines provide more effective and longer-lasting protection.
Although milder, Omicron still causes hospitalizations and deaths.
If the UK pandemic follows a similar trend to South Africa, only vulnerable people will need a fourth booster dose, Dr Fivelman said.
There will be other variants, but Omicron is likely to be the last one of concern, the expert added, with Covid-19 on track to become endemic like influenza.