Like the rest of the nation, influenza activity in the San Diego region remains elevated and widespread, according to San Diego County Health and Human Services Agency officials.
Reports of lab-confirmed influenza dropped last week to 564 cases from the season high of 692 cases the week before. A new flu death was reported last week, bringing this season’s total to 55. At the same time last season, 325 people had died from complications from the flu.
Like the rest of the country, the most commonly identified flu strain causing local illnesses is now influenza A H3N2, which tends to sicken the elderly and the very young, as well as those with chronic medical conditions. Influenza A Pandemic H1N1 continues to circulate and a low number of influenza B viruses are also being reported.
This variant of swine flu is increasing across the region, said Eric McDonald, M.D., medical director of epidemiology for the county of San Diego in a KPBS interview. The strain tends to affect seniors the most, he said.
“As more H3N2 is seen, that means it’s more likely that we’ll see older people in our community getting affected by the flu,” McDonald said. “We can expect more outbreaks, more cases being reported.”
So far this flu season, the strain responsible for the majority of cases in the region, and across the nation, is H1N1, which tends to impact people under the age of 40. The latest county influenza report shows more than 6,000 people have been sickened and 45 people have died.
But according to the Centers for Disease Control, the dominant flu strain in some parts of the U.S. has shifted to H3N2. California will likely follow the trend, McDonald said.
“One might predict that H3N2 will become a bigger problem in San Diego in the next few weeks,” McDonald said. “We’re seeing a subtle shift. Whether that means there’ll be a majority of H3N2 in the future, we just don’t know.”
McDonald said H3N2 is a seasonal flu, and it’s similar to last year’s flu strain, but not exact. Symptoms include sudden onset fever, body aches, headache, chills and fatigue.
“This is a different H3N2 from last year,” McDonald said. “It’s a different strain of flu, and there are always different strains. And as one strain starts to go down in numbers, sometimes another strain starts to go up.
The change in viral activity prompted the Centers for Disease Control and Prevention and the County Health and Human Services Agency to issue advisories to the medical community last week to continue to consider influenza as a possible diagnosis for patients with respiratory illness.
“Given the elevated level of influenza activity, the flu season is likely to last several more weeks,” said Wilma Wooten, M.D., M.P.H., County public health officer. “If you have not gotten a flu shot, do it now, especially if you’re part of the groups at higher risk of developing complications.”
The County Health and Human Services Agency publishes the weekly Influenza Watch report, which tracks key flu indicators and summarizes influenza surveillance in the region.
For the week ending March 30, 2019, the Influenza Watch report shows the following:
- Emergency department visits for influenza-like illness: 5 percent of all visits (compared to 5 percent as the previous week).
- Lab-confirmed influenza cases for the week: 564 (compared to 692 the previous week).
- Total influenza deaths to date: 55 (compared to 325 at this time last season).
- Total lab-confirmed cases to date: 8,470 (compared to 20,097 at this time last season).
How to Prevent the Flu
The Centers for Disease Control and Prevention recommends that everyone 6 months and older get a flu shot every year. The vaccine is safe and effective. It takes two weeks for immunity to develop.
Vaccination is especially important for people who are at high risk of developing serious complications from influenza. They include:
- People with chronic medical conditions, like asthma, diabetes and lung disease, even if symptoms are under control;
- Pregnant women;
- People 65 years and older; and
- People who live with or care for others who are at higher risk.
In addition to getting vaccinated, people should also do the following to avoid getting sick:
- Wash hands thoroughly and often;
- Use hand sanitizers;
- Stay away from sick people;
- Avoid touching your eyes, nose, and mouth;
- Clean commonly touched surfaces; and
- If you are sick, stay home and avoid contact with others.
The flu vaccine is available at doctors’ offices, community clinics, and retail pharmacies. If you don’t have medical insurance, you can go to a County public health center to get vaccinated. For a list of locations, visit www.sdiz.org or call 2-1-1.
This report was based on reporting by Jose Alvarez, a communications specialist with the County of San Diego Communications Office and Susan Murphy, a multimedia health reporter for KPBS.