Table 4. Characteristics of 8 children and young adults who died of influenza and had invasive methicillin-resistant Staphylococcus aureus co-infection, United States, 1998–99 through 2007–08 influenza seasons.

Patient age, y/sex	Season	Influenza type	Previous conditions	Sudden death*	MBL2 haplotype†	MBL production haplotype‡	MBL2 structural variant
29/M	2004–05	A	None	Yes	YA/O	Intermediate	rs1800450 A/G
14/M	2006–07	A	None	No	XA/YA	High	None
11/F	2006–07	B	None	Yes	YA/YA	High	None
13/M	2006–07	B	None	Yes	XA/O	Low	rs1800450 A/G
12/F	2006–07	B	None	No	O/O	Low	rs1800450 A/A
8/F	2007–08	A	Asthma	Yes	XA/O	Low	rs1800450 A/G
18/M	2007–08	A	Asthma	Yes	XA/O	Low	rs1800450 A/G
32/M	2007–08	B	Asthma	No	XA/YA	High	None

*Sudden death is defined as death occurring less than 3 days after symptom onset. MBL2, mannose-binding lectin gene.
†Per common designation for MBL2, A refers to the wild-type structural allele, O refers to any of the 3 variant structural alleles, and O/O refers to any combination of structural variant alleles. Y refers to the wild-type allele and X to the variant allele at promoter locus rs7096206 (the X/Y variant).
‡Low mannose-binding lectin (MBL) producers included MBL2 haplotypes O/O and XA/O. Intermediate producers included MBL2 haplotypes XA/XA and YA/O. High producers included MBL2 haplotypes XA/YA and YA/YA.