Since most countries have stopped counting individual swine flu cases, the figure is considered an underestimate.
WHO said there were 4,999 total deaths through Oct. 18, most of them in the Western Hemisphere. The figure was up 264 from a week earlier.
Iceland had its first swine flu death this week, and WHO said Sudan and Trinidad and Tobago also reported deaths from the virus for the first time this week.
In the United States, swine flu caused at least 95 children's deaths since April, the Centers for Disease Control and Prevention said Friday.
Forty-six states now have widespread flu activity, the CDC said, adding that only Connecticut, Hawaii, New Jersey and South Carolina are without widespread flu.
In London, drug maker GlaxoSmithKline PLC said children may only need one shot of its swine flu vaccine to be protected.
In its statement Friday, Glaxo said one dose was enough to boost children's immune systems to fight the virus, based on data from a trial in Spain in 200 children aged six months to 3 years.
Glaxo's finding comes after experts said they expected children would need two doses, since their immune systems are weaker than those of adults. Last week, rival vaccine maker Sanofi Aventis said children would likely need two doses of vaccine against swine flu, or H1N1.
GlaxoSmithKline's Pandemrix vaccine contains an adjuvant, a chemical compound that stretches a vaccine's active ingredient and increases the human body's immune response. While European flu vaccines commonly use adjuvants, there is limited data on how safe they are in groups including children and pregnant women.
