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.

The Return of Swine Flu – A Death in the U.S. and Uncertainty

Sadly, the U.S. reported its first death in a 23 month old Mexican toddler visiting in Texas.

Cases have developed in countries on at least five continents over a brief time period. The first death in the U.S. among 64 cases, which is also the first death globally outside of Mexico among 100 or more cases, is difficult to put into perspective with any confidence – especially since the baby came from Mexico. The death of a baby in the U.S. is tragic, but each year we see 36,000 deaths from influenza in our country. Influenza is always serious – even without an exotic strain from another country. We cannot at this time predict the mortality of the Swine flu outbreak, but only put in a range of 0.1% of cases to something higher such as 0.5% (seen in the 1957 “Asian” flu and 1968 “Hong Kong” flu pandemics). A 1% mortality may be worst case scenario and seems unlikely.

If more deaths are occurring in Mexico than the rest of the world, why would this happen? In both the U.S. and Mexico the same virus is attacking the same age cohort – young adults. Then any big differences would be ascribed to differences in patients. Is it possible that patients in Mexico have co-infection with a second virus? Do they have high rates of secondary bacterial pneumonia with Staphylococcus aureus or Pneumococcus? Is the particulate air pollution in Mexico City damaging airways and lungs causing more disease? Do patients have an unusually robust immune response to the virus – the so-called cytokine storm? We do not know the answers to any of these questions, but the key point is this: CDC in concert with health authorities in Mexico should perform sophisticated viral and bacterial studies, and pathology analyses on patients with severe disease and on patients who have died. Our understanding of how to manage this viral infection will be enhanced with such information.

As we prepare ourselves in the U.S. for more illnesses and more deaths from the new Swine flu, it is the uncertainty that is especially challenging. Knowing the cause of severe illnesses and deaths and the true mortality will be of critical importance.

The Return of Swine Flu: Mexico vs. U.S.

Those who boldly predict the outcome of influenza do so at their own peril.

The 2009 Swine Flu outbreak in the U.S. and Mexico is different than previous outbreaks. The key issue today is why deaths have been reported in Mexico and not elsewhere. The same virus is attacking the same age group - healthy young adults - in the affected countries. So, the difference in outcome must be differences among the patients. This is likely due to one of three things: in Mexico, the patients have more secondary bacterial pneumonia (e.g. with Staph or Pneumococcus), or co-infected with flu virus and another virus, or there is more damage to the lungs given the high level of pollution in Mexico City.

Since the cases in the U.S. are mild, it cannot be the rapid access to ICUs here that is saving lives - as some have speculated. Furthermore, the antivirals are weak therapeutic agents, which disproves that our access to therapy is saving patients with the disease.

The good news is that we have two antivirals that are effective against the circulating strain of Swine Flu. The key point, however, is that each offers excellent protection as a prophylactic agent- from recent studies of the antivirals about 70% of exposed but not ill people can be spared infection. Yet both drugs are marginal as therapeutic agents, and neither has been rigorously tested in life-threatening cases of flu. That is the reason to seek a safe and effective vaccine.

There are important lessons from prior influenza and Severe Acute Respiratory Syndrome (SARS) pandemics:

* Accurate and early reporting of all cases globally is essential for control. The delays in reporting the initial cases of SARS in China contributed to its early dissemination.

* Infection Control in hospitals must be assiduous to avoid spread to health care workers and other patients. This was noted early in Canada with the SARS pandemic, and rapid interventions led to its control there. Specifically, handwashing and prudent use of masks are helpful and effective. If the new Swine Flu strain shows occasional ability to be airborne within microscopic droplets, the use of negative air pressure rooms - if available to keep the air currents going only in the direction of the patient's room- may help.

* Lastly, the need for psychological support of health care workers was not fully appreciated early in the SARS outbreaks. These dedicated men and women are overepresented by young adults- susceptible to Swine Flu. Careful attention to their needs and support for their families would be essential.

In 1976, when my colleagues and I reported two patients in Virginia with Swine Flu, it added some concern that the original cluster at Fort Dix had spread beyond New Jersey. President Ford received impassioned advice from health policy experts at that time and strongly advocated a national vaccine program. Subsequently, there were two unexpected outcomes: The Swine Flu epidemic never materialized, and the vaccine unexpectedly caused a 7-fold increase in a neurological side effect leading to weakness and paralysis, the Guillian Barre Syndrome. A shakeup at CDC followed, and for years the public's willingness to accept vaccines was diminished.

It is unclear if Swine flu will act more like the devastating avian flu pandemic of 1918-19 or the fizzled Swine flu outbreak of 1976. However, the latest "influence" to visit itself upon the citizens of the world reminds us that epidemics are part of the natural interaction of people and microbes throughout civilization. Yet each time we react as though we have discovered something new. The only really new things are our surprise and consistent inability to recall all of the lessons from prior visitations.