Washington, Feb 20 : The US Food and Drug Administration (FDA) is considering approving a fourth dose of a Covid-19 vaccine later in the year, the Wall Street Journal reported. Citing people familiar with the matter, the report claimed that the health regulatory body has begun reviewing data that could lead to clearing a second booster dose of the Pfizer, Moderna vaccines by September. However, the planning is still in early stages. The authorisation will also depend on ongoing studies establishing that a fourth dose would increase people's molecular defenses that waned after their first booster and reduce their risk of symptomatic and severe disease, the report said. The FDA did not comment on the matter. But, the agency last month cut short the duration to get a booster dose of Covid-19 vaccines from Pfizer and BioNTech as well as from Moderna, in a bid to provide better protection sooner against the Omicron variant. Israel became the first country, in late December last year, to begin the rollout of a second booster dose to people over-60s, healthcare workers and those with weakened immune systems. The US has already approved the fourth dose for immunocompromised people, such as those living with HIV or certain transplant recipients. Other countries that have approved the fourth shot include the UK, Chile. Israel is now considering the fourth dose for all adults, above the age of 18, in the wake of a surge in infections driven by the Omicron variant. South Korea became the latest country, last week, to begin administering the fourth shots of Covid vaccines for people at high risk. However, the country's health regulators do not have plans to expand the fourth dose to all adults. Sweden's Health Agency also, last week, recommended people aged 80 or above should receive a fourth jab to ward off waning immunity amid the rampant spread of the Omicron variant. Several European countries including Hungary and Denmark have also considered rolling out the second booster dose in the wake of the vaccine evading the Omicron variant. /IANS