Povidone-iodine is also efficient against fungi and viruses (including HIV and "Herpes simplex"). It is used in pleurodesis (fusion of the pleura because of incessant pleural effusions). For this purpose, povidone-iodine is equally effective and safe as talc, and may be preferred because of easy availability and low cost. There is tentative evidence that chlorhexidine and denatured alcohol used to clean skin prior to surgery is better than povidone-iodine with alcohol; however, the evidence is not strong enough as of 2015 to determine routine practice. PVP-I is contraindicated in patients with hyperthyroidism (overactive thyroid gland) and other diseases of the thyroid,
Iodine filtering and purification the iodine is packed. These sources ensure that Chile and Japan are the largest producers of iodine today. Alternatively, the brine may be treated with silver nitrate to precipitate out iodine as silver iodide, which is then decomposed by reaction with iron to form metallic silver and a solution of iron(II) iodide. The iodine may then be liberated by displacement with chlorine. Unlike chlorine and bromine, which have one significant main use dwarfing all others, iodine is used in many applications of varying importance. About half of all produced iodine goes into various organoiodine compounds; another 15%