Changes in anti-group a rotavirus antibody seroprevalence and levels in the Western Gyeongnam province of Korea over 16 years

Abstract

To observe how anti-group A rotavirus antibody seropositivity rates and levels have changed in the western region of Gyeongnam Province, 2,030 serum samples collected at four collection periods (1989-1990, 1994-1995, 1999-2000, and 2004-2005) were tested by Enzyme-Linked Immunosorbent Assay for IgG, and IgA antibodies reacting to recombinant VP6 protein. The seroprevalences exhibit no regular patterns over a 16-yr period. For all four collection periods, the anti-rVP6 IgG levels rose steadily during the first 5 months of life, after which they remained high. However, the 2-9 yr and 10-39 yr groups had significantly higher IgG levels in 1999-2000 and 2004-2005, respectively, than in the other collection periods. The 1-5 mo, 40- ≥ 60 yr, and 4-29 yr groups had significantly higher IgA levels in 1989-1990, 1999-2000, and 2004-2005, respectively. The 4 yr (25.0%), 5-9 yr (18.8%), 10-14 yr (41.1%), 20-29 yr (35.0%), and 30-39 yr (20.0%) groups in 2004-2005 had significant higher IgA seropositivity rate compared to the other three collection periods. These observations suggest that in the western region of Gyeongnam Province since the late 1990s, rotavirus reinfection has occurred more frequently than previously, with all ages being at risk.

Keywords: ELISA; Rotavirus; Seroepidemiology; VP6.

Fig. 1

Anti-recombinant VP6 protein IgG antibodies at four serum collection periods between 1989 and 2005. The IgG levels of each age group at each time point are expressed as median optical densities. For all collection periods, the optical density began to increase in the 0-5 mo group, after which it remained continuously high. ^*Statistically significant differences between the four time periods in terms of optical density (P < 0.05); ^†The median optical density (OD) in 1999-2000 was higher than the median ODs in 1989-1990, 1994-1995, and 2004-2005; ^‡The median OD in 1999-2000 was higher than the median ODs in 1989-1990, 1994-1995, and 2004-2005; ^§The median OD in 1999-2000 was lower than the median ODs in 1989-1990, 1994-1995, and 2004-2005; ^¶The median ODs in 1994-1995 and 2004-2005 were higher than the median ODs in 1989-1990 and 1999-2000.

Fig. 2

Anti-recombinant VP6 protein IgG seroposivity rates at four serum collection periods between 1989 and 2005. At all collection periods, all age groups exhibited IgG seropositivity rates of almost 100%.

Fig. 3

Anti-recombinant VP6 protein IgA levels at four serum collection periods between 1989 and 2005. The IgA levels of each age group at each time point are expressed as median optical densities. Compared to the other periods, the 1-5 mo age group had higher IgA levels in 1989-1990, the 4-29 yr age groups had higher IgA levels in 2004-2005, and the 40- ≥ 60 yr age groups had higher IgA levels in 1999-2000. ^*Statistically significant differences between the four time periods in terms of optical density (P < 0.05); ^†The median optical density (OD) in 1989-1990 was higher than the median ODs in 1994-1995, 1999-2000, and 2004-2005; ^‡The median OD in 2004-2005 was higher than the median ODs in 1989-1990, 1994-1995, and 1999-2000; ^§The median OD in 1999-2000 was higher than the median ODs in 1989-1990, 1994-1995, and 2004-2005.

Fig. 4

Anti-recombinant VP6 protein IgA seropositivity rates at four collection periods between 1989 and 2005. The IgA seropositivity rates showed a similar bimodal pattern in 1989-1990, 1994-1995, and 1999-2000, namely high seropositivity rates in young children and 10-40 yr-olds and low seropositivity rates in 2-4 yr-olds.