Notes on H1N1 in Chile

I recently made rounds in the adult and pediatric ICUs of one of the university hospitals in Chile, Hospital Clínico UC. The staff there confirmed that about one-third of non-ICU patients that are admitted have no fever. Even more interesting, half of the outpatients with confirmed H1N1 also exhibit no fever.

Physicians from both ICUs described screening patients with no other symptoms than rhinorrhea (runny nose), that turned out to have confirmed cases of H1N1.

The lesson here is that the clinical expression of H1N1 is extremely broad. Screening only the patients who exhibit a high fever will result in many overlooked cases. Further, when counting infected patients, if fever is part of the case definition, the denominator will be greatly underestimated.

It is surprising to see how differently H1N1 is being managed throughout Latin America, especially between Chile and Brazil. In Chile, clinicians make a clinical diagnosis—confirmation is not essential—and Oseltamivir is administered. The drug is given to patients free of charge.

H1N1 and Pregnancy

During my travels to Latin American countries contending with the disease in their winter season, I learned that pregnancy has been recognized as a risk factor for serious disease outcome with influenza strains in general. Pregnant women who contract the current version of pandemic H1N1 influenza risk being in an ICU and dying of the infection. H1N1 targets young adults - not the very young children and elderly as past circulating strains of seasonal influenza do. As a result, more young woman are at risk.

Two risk factors- morbid obesity and pregnancy - both conditions overrepresented among dying patients with H1N1, share a degree of insulin resistance. This is a metabolic condition which can predispose to infection. It is also possible that pregnancy and obesity have low lung volumes in common that may be contributing to severity. While this is based on speculation, it is my hope that scientific studies will examine why H1N1 causes such severe disease in pregnancy.

The key public health implications are that pregnant women should be a high priority to receive a future safe H1N1 vaccine. In the meantime they should avoid contact with any patients who might have the pandemic strain.

During my time in Latin America, I uncovered the following supporting evidence:

• In Brazil, I learned that pregnancy was a risk factor for needing intensive care treatment after infection with H1N1.

• In Columbia, one of seven reported deaths in adults with H1N1 was in a pregnant woman.

• In Argentina, of 85 deaths after H1N1 in the region of Buenos Aires, one fourth were in pregnant women. Obesity, which was recognized as a likely risk factor for dying in Mexico and more recently in the United States, was a close second to pregnancy among those dying of H1N1 in the same region.

Notes on H1N1 in Brazil

In Brazil I had dinner with two former fellows and their colleagues, where I gained new insights into the H1N1 situation in Latin America. Here there has been an upsurge of reported cases. This increase appears to correlate with vacationers returning from Argentina and Chile with the virus.

The Brazilian government is managing the outbreak in a way unlike any other country I have examined. Patients with influenza-like illness (ILI) (i.e. fever with either cough or sore throat) in São Paulo, a mega-city of approximately 15 million, can be screened—by law—at only seven hospital emergency rooms.

Here, patients are screened using an immunoblot procedure with a sensitivity of 70 percent. The Oseltamivir drug is administered if (and only if) a patient with a positive screen also has some defined high-risk factors. A confirmation polymerase chain reaction (PCR) test is then done and sent to a single lab, responsible for the entire city’s PCR evaluation. It takes more than ten days for the PCR results to become available.

To me, the most troubling issue is that infectious disease specialists here cannot write a prescription for Oseltamivir or screen for flu. The government grants this authority only to the physicians at the seven designated emergency departments.

Notes on H1N1 in Argentina

I recently visited Argentina. This country’s population is one-third the size of Mexico’s, though they have reported even more deaths from the virus. The government here is taking strict steps to try to limit the spread of H1N1 among its population.

Schools here are currently closed, and the government has ordered them to remain closed for a full month. Large gatherings and meetings have been prohibited throughout the country. Pregnant women and other high-risk young adults are not allowed to go to work.

As soon as an Argentinean experiences symptoms, they are sent directly to the hospital for testing. However, Oseltamivir—an anti-influenza antibiotic—is given only to young adults here.

It is interesting to observe such major differences in the way H1N1 is being managed in Latin America. I will report back more of what I’ve learned in the coming days.

New Outbreak in Mexico

In recent discussions with the director of the Institute for Respiratory Diseases and other physicians, I learned more about a new surge in H1N1 in Mexico. The most severe cases are occurring in the state of Chiapas. Patients there who are on respirators currently have a 50 percent mortality rate. This is very similar to the rate for patients who were initially on respirators at the Institute for Respiratory Diseases. The Institute recently sent some faculty and medical residents to Chiapas to add greatly needed expertise to their efforts there.

By December of this year, Mexico will have 20 million doses of a vaccine for H1N1 available. In the meantime, they are wrestling with how to choose the population that will receive the vaccine. Should it be administered to the high-risk young adults? Children, who most frequently transmit the virus? Or pregnant adult women? The next difficult decision will be choosing which people in that targeted group will receive the vaccine.

This is indeed a complex situation for Mexico, which they are dealing with in a very thoughtful and organized manner. I have traveled to other countries in Latin America contending with the disease in their winter season. It appears there is a clear contrast in response to H1N1, and I gained first-person insights on the situation there, which I will write posts on soon.