Health experts say extraordinary measures against swine flu most notably quarantines imposed by China, where entire planeloads of passengers were isolated if one traveler had symptoms — have failed to contain the disease. Despite initially declaring success, Beijing now acknowledges its swine flu outbreak is much larger than official numbers show. China’s official count of nearly 70,000 reported illnesses with 53 deaths is dwarfed by estimates of millions of cases with nearly 4,000 deaths in the United States, a nation with about a third of China’s population. China’s Health Minister Chen Zhu defended his country’s aggressive quarantine policy, telling the AP on Wednesday that the measures helped slow the spread of the virus long enough for China to develop a vaccine, which authorities are now scrambling to administer.