UPDATE 1-WHO likely to give H1N1 jab guidance on Monday

* WHO expert set to give briefing on flu vaccine Monday

* H1N1-resistant cases have raised interest in jab

(updates with WHO spokeswoman saying briefing likely on Monday)

GENEVA, July 10 (Reuters) - The World Health Organisation (WHO) will probably hold a media briefing on Monday to issue guidance about the need for a H1N1 influenza jab, a WHO spokeswoman said on Friday.

"The recommendations are still in the process of being developed," Fadela Chaib told a news briefing in Geneva, where the United Nations agency is based.

"The press conference will probably be on Monday," she later told Reuters.

Marie-Paule Kieny, WHO director of the Initiative for Vaccine Research, would give a news briefing once the recommendations emerging from the closed-door WHO meeting on Tuesday are approved by WHO Director-General Margaret Chan.

The WHO raised its influenza pandemic alert to the highest level on June 11 in response to the worldwide spread of H1N1, a newly discovered virus strain commonly known as swine flu.

Vaccine makers such as Sanofi-Aventis (SASY.PA), Novartis (NOVN.VX), Baxter (BAX.N), GlaxoSmithKline (GSK.L) and Solvay (SOLB.BR) are seeking WHO guidance about whether to ramp up production of jabs for the strain, to keep making seasonal flu vaccines, or to produce a combination.

The discovery of three isolated cases of H1N1 flu in Denmark, Japan and Hong Kong that resisted treatment with the anti-viral drug Tamiflu, made by Roche (ROG.VX) and Gilead (GILD.O), has raised interest in a jab to prevent infection.

The WHO said earlier this week that Tamiflu-resistant H1N1 flu does not appear to be spreading in a sustained or worrisome way. All patients with the resistant variety have recovered fully, and their viruses were sensitive to treatment with the other anti-viral recommended by the WHO, the inhaled drug Relenza made by Glaxo under license from Biota (BTA.AX). (Reporting by Laura MacInnis and Stephanie Nebehay; Editing by Louise Ireland)