Influenza disease is one of the most seasonal diseases that affects many people all over the world. influenza 2019 will be specially discussed in this topic.
What is influenza?
It is a viral respiratory disease that affects the nose, throat, and lungs caused by viruses of the family Orthomyxoviridae.
There are 3 types of viruses A, B, and C.Influenza A and B are associated with seasonal influenza, and most outbreaks and epidemics of influenza. Type C is rare and does not usually cause epidemics or outbreaks.
It easily passes from one person to another.
It can make a bacterial infection in the body causing pneumonia and even death.
Seasonal influenza-like influenza 2019 is annual influenza that affects people in winter especially in the period between November and April.
Seasonal influenza 2019
It was a severe season with a high number of deaths and patients all over the world.
Influenza 2019 in the United States
It was from (October 1, 2019, to April 4, 2020). It was expected to be one of the worst seasons in several years.
It came in two waves with a hard effect on children.
The season began in October, so it was earlier than usual with the expected wave of influenza B virus then the second wave came with the presence of influenza B viruses like (H1N1).
So, the number of dead children was higher in late February than in the previous seasons for the past ten years. It was approximately 67% sociated with influenza B viruses.
Statistics of influenza 2019 season in the USA
According to (CDC) the center for disease control and prevention, influenza 2019 caused 39 to 56 million flu illnesses.
Also, it caused 410,000 to 740,000 hospitalizations,18000 to 26000 visits to doctors, and about 24,000 to 64,000 deaths.
The 2019 season recorded higher numbers because of the Covid-19 pandemic. The preliminary estimates had adjusted down when the season was officially closed.
The decline in cases by April 2020 was due to the effect of lockdowns aimed at Covid-19, shortening influenza 2019 season by 5 weeks.
Vaccination for influenza 2019
According to survey data, CDC estimated that 51.8% of persons from 6 months to older are vaccinated in the 2019_2020 flu season with an increase of about 2.6% from the previous seasons.
Vaccines used for this season
according to FDA's vaccines and Related Biological Products Advisory Committee
. An A/Kansas/14/2017 (H3N2)-like a virus
. An A/Brisbane/02/2018
(H1N1) pdm09-like virus
. B/Colorado/06/2017-like virus (B/Victoria)
According to the CDC, the vaccines were 39%,30%, and 45% effective against influenza A or B viruses, A(H1N1)pdm09 viruses, and influenza B/Victoria viruses, respectively.
Influenza 2019 in Australia
2019 saw the highest number of cases on record in Australia due to the earlier outbreaks. This flu season affected 310,000 Australians which is 80% higher than in 2018.
It was seven times greater than Australia's previous 18-year average.
They put it down to higher tourist numbers, more Australians traveling overseas, and climate conditions.
It had mainly virus A(H3N2) followed by A(H1N1)PDM, and some B's.
Statistics of Australian influenza 2019
. The high number of hospital admissions 3915
. 6.3% admitted directly to ICU
. Influenza deaths 902
The majority of deaths were due to influenza A(96%).128 were associated with influenza A (H3N2), 29 with influenza A(H1N1)pdm09, and 30 with influenza B.
Vaccines for Australian influenza 2019
The strains in southern hemisphere seasonal influenza vaccines are listed below.
1. The egg-based quadrivalent influenza vaccines contain the following four viral strains:
. An A/Michigan/45/2015 (H1N1)pdm09-like virus
. An A/Switzerland/8060/2017 (H3N2)-like a virus
. A B/Colorado/06/2017-like virus (B/Victoria/2/87 lineage)
. A B/Phuket/3073/2013-like virus (B/Yamagata/16/88 lineage)
2. The egg-based trivalent influenza vaccines contain the following three viral strains:
. An A/Michigan/45/2015 (H1N1)pdm09-like virus
. An A/Switzerland/8060/2017 (H3N2)-like a virus; and
. A B/Phuket/3073/2013-like (B/Yamagata/16/88 lineage)
Influenza 2019 in Canada
The season began on week 47(November 17 to 23, 2019), peaked in late January (week 5), and ended early and abruptly on week 13 (March 22 to 28, 2020), eight weeks earlier than the average end of the season.
Strains of influenza 2019 in Canada
Influenza A was the main type in this season with 59%of detections and A(H1N1) the dominant subtype (68% of sub-typed influenza A).
Influenza A affected all ages with influenza A(H3N2) primarily affecting adults 65 years of age and older and influenza A(H1N1) primarily affecting individuals under 65 years of age. Influenza B had an effect on younger people about 5years and younger.
Statistics of seasonal influenza 2019 in Canada
Firstly a low number of reported influenza detections, outbreaks, and hospitalizations were recorded from mid-march to the end of the season.
The activity of the season was during (mid-November to mid-March).
It recorded cases higher than normal of all seasonal influenza types and subtypes.
In 2019, there were 18 deaths from influenza per 100,000 population, an increase from previous years.
Influenza 2019 in Alberta
This season began on week 44 in late October and finished early on week 14(early April). It was by the public health intervention for COVID-19.
Strains of influenza in this season
The predominant strain in this season was influenza B (44% of cases). There was a smaller wave of influenza A (H1N1) that happened at the end of the season, especially at the third peak.
Statistics of influenza 2019 in Alberta
61 ICU admissions
A total of 191 outbreaks were reported in Alberta.
Vaccines for influenza 2019 in Alberta
It covered 33% with a 2% increase over the previous season.
It was 61% by pharmacists
22% by public health
17% by other providers