Changing the Way We Think About a Pandemic

WHO has recently declared a flu pandemic – the first since 1968. So we might ask ourselves, “what is different?” Moving from a phase 5 pandemic alert to a level 6 alert currently only implies that there is a sustained spread in different continents.

But such a move is confusing since each year the seasonal flu – which bears similar characteristics – kills 500,000 people globally, yet no pandemic level 6 has ever been declared. In contrast, the current H1N1 Swine flu has killed fewer than 150 people. Shouldn’t the pandemic scale be more focused on severity and the resources needed to control epidemics?

To me, a pandemic implies a response to an infectious threat that requires an international surge in capacity for resources, communication and cooperation. Thus, the two key elements determining the pandemic alert level and necessary response are efficiency of transmission and disease severity.

One could insist that sustained transmission of a totally new infectious agent should be considered for a level 6 pandemic scale. But what do we do if H1N1 stays around for three years? When does “new” end? To avoid confusion, I think the requirement for surge capacity is key. Thus, a global outbreak of a common cold virus would not reach a high level on the pandemic scale, since few new resources would be needed and severity is not an issue.

For resources, I would include the types (food, water, medical equipment, drugs, vaccines, etc.), the quantity, and the effective delivery systems. One might also include the estimate of the country’s GDP that will be needed to support the control measures. In Mexico, it has been estimated that over 4.5% of its GDP will be needed to cover the costs of managing H1N1. For communication, I would include the measures of the pandemic transmission and severity as mentioned above, and the rate of resource utilization for a region or country. For cooperation, I mean the legal, administrative, medical and other types of required sharing across regions and countries.

Once we have the definitions, we could construct a hierarchy of levels of Pandemic Threat based on the increasing need for resources, communication and cooperation across regions and countries, and these would be paralleled by increasing rates of transmission and severity.

Progressing from the bottom end of the Pandemic Threat Scale to the top would imply increasing transmission and severity as well as increasing surge capacity for resources, international communication and cooperation.

An implication of such a system is that we need international agreements before and not after a pandemic. The World Bank for example might reward a country for early reporting of a new disease as an incentive to the country worried about the economic consequences of transparency. Countries would have to accept help when it is needed and not be constrained by their own national laws. A new Pandemic Threat Scale will require unprecedented international cooperation that does not exist today. But surely it is needed, and H1N1 has shown our lack of clarity in 2009.

H1N1 in Mexico – Lessons Learned

The Mexicans have taught the world that transparency and full disclosure was brave and admirable and saved countless lives but came at the price of severe economic consequences. The argument made by me and others after SARS that the World Bank should provide incentives to countries for rapid reporting of novel pathogens causing epidemics seems to still be valid today.

A week or so after the outbreak, a flight to Mexico from Atlanta was only 15% occupied, and on arrival the airport was nearly deserted. I had been asked to Mexico City by my colleagues at the National Institutes of Respiratory Infection and planned to make rounds with them in the wards and ICU’s.

The city was awakening from the infection control measure called social distancing. The traffic on this mega city of 20 million was only half of its usual density compared to my experiences in 25 prior trips. Cabbies still wore masks as did the staff in all restaurants, most of the police officers, and perhaps 10-20% of the citizens walking around. On that day the swimming pools and restaurants were opening for business; football (soccer) was about to resume, and schools were opening on Monday, May 11^th.

Almost two weeks earlier Mexican health authorities announced to the world the increasing number of cases and deaths from the new strain of influenza virus fully cognizant of the economic consequences. In a brief 10 day interval they made a critical decision for transparency, in bold contrast to the 110 day interval before the world learned about SARS in China. Because there was no vaccine and no certainty that the available drugs to treat influenza would be effective, the only option left was social distancing.

On Friday and Saturday I made rounds on the wards and ICUs of the National Institute of Respiratory Infection and National Institute of Nutrition. Patients in their 20s, 30s, and 40s were on respirators, and so the inhuman statistics now had meaning. In the last few weeks, those in ICUs intubated and on mechanical ventilators included a bus driver, a housekeeper from one of the hospitals, an anesthesiologist and a mechanic. H1N1 appears to be an equal opportunity virus.

Outside the hospital, medical residents in training and wearing masks were screening all people entering the hospital. At another table nurses and physicians had set up a center for health care workers and their families to answer any questions, to give the 24/7 hotline and instructions. They were essentially managing fear and offering psychological support. Their creative implementation of triage outside of the hospital entrances is wise.

On Saturday rounds in the ICU at the Nutrition Institute, a young man had just died and a second had relapsed and returned from the ward to be intubated. Influenza has the ability to cause severe illness and kill healthy young people. We have been fortunate in the U.S. with mild cases, but complacency would be a foolish path ahead.

Influenza H1N1 may rear its dark side yet in the U.S. It may soon advance to South America where the winter is approaching, and may resurface with a new face in the Northern Hemisphere in the fall and winter 2009-2010. We have time to prepare for a vaccine if needed, and we certainly can applaud the Mexican health authorities and learn from their remarkable encounters with H1N1.