With several countries now confirming human cases of a new influenza A virus, Anastasia Moloney examines whether the local and international response to the outbreak was quick enough.
As the tally of confirmed cases of the influenza A (H1N1) virus level off in Mexico City, questions are being raised about whether health authorities in and outside of Mexico reacted swiftly enough to the outbreak.
In early April, analysts working at Veratect—a US biosurveillance consultancy—picked up a string of reports about unusual respiratory diseases in several states in Mexico, including a health alert in the state of Veracruz on April 6. “Things in Mexico were looking very strange. Locals were very concerned about what was going on”, said Robert Hart, director of Veratect.
Urgent warning alerts posted by local health authorities in Mexico continued over the following days. On April 16, Veratect reported that Mexican health officials were concerned about unusual cases of pneumonia in a hospital in the Oaxaca state. “By then, I knew there was a serious problem”, said Hart. This information was available to leading US and international health agencies hooked up to Veratect's alert feed service. The Pan American Health Organization (PAHO) had also been picking up these alert feeds.
WHO has also said it was monitoring the situation from April 10 on the basis of reports from Mexican authorities about unusual respiratory cases, and had immediately asked Mexican authorities to investigate. Health officials in Mexico reported back to WHO concluding there was no epidemic. At this stage, the new A (H1N1) virus had not yet been identified.
On April 16, the death of a woman with diabetes from acute pneumonia in the Oaxaca state prompted Mexican health authorities to alert PAHO about a possible epidemic brewing.
WHO issued its first public response about the influenza A outbreak on April 24, and held its first emergency meeting the next day. That was 18 days after Mexican health officials first raised the alarm locally. By then, the virus had spread across Mexico's borders to the USA. It was when the USA confirmed seven cases of influenza A (H1N1) on April 24 that international agencies started to respond quickly.
Although it is difficult to reconstruct the hazy timeline of events, the Mexican experience has exposed delays and apparent flaws in procedures to detect disease outbreaks as set out in the International Health Regulations in 2007, which aimed to strengthen WHO's response capacity after the epidemic of Severe Acute Respiratory Syndrome.
PAHO spokesperson, Daniel Epstein, confirms that PAHO received alerts from Veratect on April 16, but defends criticisms that the agency was slow to act. “There was no time delay”, he said, “a cluster of influenza cases in one country does not necessarily have international significance”. 8 days later, laboratory tests done in Canada confirmed that 18 of the 51 tests from Mexican specimens for suspected A (H1N1) came back positive. 12 of those were found to have the identical genetic pattern as the influenza A (H1N1) viruses from California, explains Epstein. “These were crucial links”, said Epstein. 2 days later, WHO raised its alert level from 3 to 4 (of 6).
People have been ready to point the finger of blame. Miguel Angel Lezana, director of the National Epidemiology Center in Mexico City, has said PAHO should have acted more quickly based on the alerts about unusual outbreaks of seasonal influenza sent to the international agency in mid-April. However, on May 1, Mexico's health minister, José Ángel Córdova, put these remarks down to a “confusion” and downplayed any tensions while emphasising there had been “no contradictions or difficulty” between WHO and the Mexican health ministry.
Mexico's response to the outbreak has also been criticised. Agenor Álvares da Silva, head of the Brazilian National Health Surveillance agency, has questioned the slow response of Mexican health authorities since, he says, alarm bells had been raised in March, but international health authorities were only informed about a