Puerto Rico Declares An Early Influenza Epidemic

#17,754

While influenza activity remains low across much of the country, flu has been running unusually high on the island of Puerto Rico for several weeks (see chart Epi Week #43 below), prompting their health department to declare an epidemic yesterday. 

This is the first flu epidemic declaration in Puerto Rico since 2016, and it comes unusually early in the year.  Up until a few weeks ago, the majority of cases were from influenza B, but influenza A (H1N1) became dominant in week 42. 

Last Friday's (Week 43) local flu report stated:

• Predominantly, around 52.76% of the season's reported cases have been identified in the pediatric population (0 – 19 years).

• Preliminarily, it is the eleventh consecutive week with the number of influenza cases on an increasing trend.

• Since epidemiological week 27 (2023), it was observed that cases of influenza type B were the majority of cases for weeks 27 – 41 of the 2023 – 2024 Influenza Season. However, for the week of this report , 63.9% of cases with valid laboratory evidence were influenza type A.

• For the week of this report, a total of 35 outbreaks were identified in educational institutions in 7 health regions. They are distributed as follows: 31 in public schools and 4 in private schools.

While seasonal H3N2 often produces more severe flu seasons - hitting the elderly particularly hard - H1N1 tends to affect children, adolescents, and young adults the hardest.  We can see that impact on the (age 0-19) pediatric age groups in the following chart from last week's flu report.

The translated announcement follows, after which I'll have a brief postscript. 

Machine Translated by Google

HEALTH DEPARTMENT

Health declares Influenza Epidemic

Since 2016, no influenza epidemic has been declared in Puerto Rico

(San Juan, Puerto Rico - November 9, 2023) - The Secretary of the Department of Health, Carlos Mellado López, accompanied by the main epidemiology officer, Melissa Marzán, and the main medical officer, Iris Cardona, reported that he raised the classification to influenza epidemic.

The secretary explained that this week fatalities increased to 42 and 903 hospitalizations and 25,900 cases were recorded so far in the influenza season, which began in July.

“This epidemic declaration is to alert and inform citizens about the actions we must take. This is not the time to be alarmed, but to prepare to help prevent the increase in the spread of this virus. Health providers are already working with measures to reduce the spread and prevent the virus. Fortunately, we have enough detection tests, vaccines and treatments required to deal with influenza cases and they are all accessible and distributed throughout the Island,” said Mellado López, explaining that there is a guide to concrete actions to confront the spread of this virus.

The pediatric population between 0-19 years old has been the most affected this season with13,666 cases reported, the group of adults between the ages of 20-59 years amounts to 9,656 cases, while 2,578 cases have been registered in older adults. The sustained increase in influenza cases has been reflected for the past twelve consecutive weeks.

Last season (2022-2023) closed with 31,710 cases, 1,224 hospitalizations and 15 fatalities. According to the historical summary of influenza seasons, 2016 was the year in which the most cases were recorded with 53,708. However, in 2015 there were 25 fatalities, while in 2018 there were

They accumulated 2,407 hospitalizations. This year (2018) accumulated the highest number of reported hospitalizations.

“The current influenza season began above the alert threshold early and has recently shown epidemic behavior with 5.7 times more cases compared to last season at this time,” said Dr. Melissa Marzán, Chief Epidemiology Officer. “The epidemic declaration is based on a methodology that consists of: the reporting of cases exceeds the alert threshold for at least four consecutive weeks and represents close to 50% of the total cases registered for the 2023-2024 Influenza Season .

In addition, it is required that cases be identified in all health regions of Puerto Rico and that there be an incidence level ÿ100 cases per 100,000 people, or, that the monitoring system of the Centers for Disease Control and Prevention reach a high level (red). “All these requirements have been met,” he stated.

For her part, Dr. Iris Cardona, Chief Medical Officer, highlighted that “the call is simple, get vaccinated. Vaccination is the main shield against some diseases and everyone over six months of age is eligible to receive it. It is available around the Island at vaccination providers, community and chain pharmacies and at vaccination activities organized in shopping centers. “We are also vaccinating at school.”

The vaccine, along with the respiratory disease prevention measures that citizens have practiced over the past three years, will help put a stop to the influenza virus. You are encouraged to wash your hands, disinfect frequently touched surfaces, and stay home if you are sick. “If you have fever, chills, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, tiredness, vomiting or diarrhea, it could be influenza. Get tested and if it is positive, seek to be evaluated by a doctor.”

The Health Department's goal is to vaccinate as many people as possible before the Christmas holidays. “We already have the experience of how to combat the disease. We know that influenza has a period where transmission is usually high. If we do our part, get vaccinated and protect ourselves, we will stop the disease,” Mellado concluded.

Vaccination events are scheduled at the Plaza las Américas shopping centers (November 24, 25 and 26), San Patricio Plaza and Plaza del Caribe (November 17 and 18), Laguna Garden Shopping Center (November 17) and Mayagüez Mall , Montehiedra and Las Catalinas (November 18). Influenza vaccines are free of cost.

On the other hand, in agreement with the Department of Education, schools are being visited to promote prevention measures among the student population.

To find your nearest vaccination center visit www.salud.pr.gov/influenza or call 787-522-3985. You can also call that phone number to arrange at-home vaccinations for bedridden people.

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As today is a federal holiday, we won't get our weekly Fluview Report from the CDC until Monday. Although flu reports have been ticking upward in the Southeastern United States, we've yet to see a major surge in cases. 

What we have seen reported has been predominantly H1N1, however, a strain that has not dominated since the truncated (by COVID) 2019-2020 flu season. 

Between a 3+ year absence - and continued antigenic changes - community immunity to H1N1 is probably low, which may explain the early jump in cases in Puerto Rico.  

Which means, if you haven't already gotten your flu shot - and want to be as protected as possible before the Thanksgiving travel holidays - you'll want to schedule that shot in the next few days.