Zbl. Bakt. 276, 540-547 (1992) © Gustav Fischer Verlag, StuttgartlNew York

Prevalence of Antibodies to Hepatitis Viruses in Blood Donors with a Clinical History of Hepatitis R. VRANCKX 1 and L. MUYLLE 2 National Viral Hepatitis Centre, Institute of Hygiene and Epidemiology, 1050 Brussels, Belgium 2 . Antwerp Transfusion Centre, Belgian Red Cross, 2520 Edegem, Belgium 1

With 3 Figures· Received January 18, 1991 . Accepted in revised form November 5, 1991

Summary A comparison between the 1979, 1982 and 1989 findings indicates that the number of adults susceptible to HAV infections has increased. This fact should be given attention in view of the strongly altered travelling pattern of fairly large sections of the population. It should also be kept in mind that the group of adults born between 1951 and 1960 comprises those adults who have the most frequent contacts with younger children being at the greatest risk of acquiring HAV infection. Zusammenfassung Ein Vergleich zwischen den Pravalenzziffern fUr 1979, 1982 und 1989 zeigt an, dag die Zahl der flir HAV-Infektionen empfanglichen Erwachsenen zugenommen hat. Dieser Tatsache sollte Beachtung geschenkt werden, da sich die Reisegewohnheiten erheblicher Teile der Bev6lkerung stark verandert haben. Es sollte auch daran gedacht werden, dag die Gruppe der zwischen 1951 und 1960 Geborenen die Erwachsenen umfagt, die am haufigsten Kontakt mit Kleinkindern haben, welche das hOchste Risiko flir eine HAV-Infektion aufweisen.

Introduction Viral hepatitis is a major health problem worldwide. Improvements in hygiene and socio-economic conditions in the developed countries have reduced its incidence. Recent advances in vaccine research and development have contributed to a further decline in hepatitis B virus (HBV) infections. The same development is to be expected when vaccines against hepatitis A virus (HAV) and hepatitis C virus (HCV) become available in the near future. Nevertheless, viral hepatitis infections are still among the major unconquered reportable viral diseases in many developed countries. Until hepatitis A virus (5) and

Prevalence of Antibodies to Hepatitis Viruses in Blood Donors

541

hepatitis B virus (1) were identified and specific diagnostic tests developed, they had been reported under several names: HAV infections as infectious jaundice, epidemic hepatitis, infectious hepatitis and others; HBV infections as serum hepatitis, parenteral hepatitis, transfusion hepatitis, etc. (14). Originally described by Rizetto (7) as a new HBV antigen-antibody system, the delta agent has now been characterized as a defective RNA virus that can replicate only in the presence of HBV. This RNA virus is now called hepatitis D virus (HDV). When diagnostic methods for HAV and HBV were developed, it became clear that part of the recorded viral hepatitis infections was caused by unknown agents. On the 23rd Meeting of the European Association for the Study of the Liver (1988, Leuven, Belgium), evidence was reported for the existence of two NANB hepatitis viruses (8): an enterically transmitted virus (hepatitis E virus, HEV), and a parenterally transmitted virus (hepatitis C virus, HCV). Choo and colleagues adopted a new approach to characterize HCV and developed the first HCV-antibody detection test (3). In 1979 and 1982, epidemiological data about the prevalence of HAV and HBV markers among Belgian blood donors were collected (9, 11). In 1989, we again selected a number of blood donors on the basis of their medical histories, which indicated an episode of viral hepatitis. In this study we have compared the following: in respect of HAV infections, the results of 1979, 1982 and the new results of 1989; in respect of HBV infections, the results of 1982 and the new results of 1989. These findings are supplemented with the new 1989 data on HCV infections. Materials and Methods Two groups were studied, both from the volunteer blood donor population of the Antwerp area, sampled in 1989 from 4833 blood donors. Group A: From 4833 blood donors chosen at random, we selected 319 (6.6%) on the basis of their medical history which indicated an episode of viral hepatitis. The exact year of infection was also known. The true nature of this viral hepatitis infection was ascertained by serological assay. Group B: Blood donors (N = 301, mean age: 39 years) were selected at random from the group of 4833 blood donors. All sera were tested: a) for antibodies to HAV: anti-HAV (IgG/lgM) using the HAVAB EIA kit (Abbott), positive results being confirmed by an Icon technique (Hybritech); b) for antibodies to HBV-core: anti-HBc (IgG/lgM) using the AB-Corek RIA kit (Sorin); c) for antibodies to HCV (ClOO-3): anti-HCV using the EIA kit (Ortho), positive results being confirmed by a neutralization technique (Abbott). Results Group A

The results of the serological tests for the presence of specific antibodies to HAV, HBV and HCV are shown in Table 1. In 278 (87.1 %) of the 319 blood donors, the history of hepatitis was most probably due to an HAV infection. In 21 (6.6%) sera we found antibodies to HAV and HBV, and in 5 (1.6%) sera, we found antibodies to HAV and HCV. This means that 304 (95.3%) subjects of this group had had a hepatitis A infection in the past.

542

R. Vranckx and L. Muylle

Table 1. Distribution of species antibodies to HAV, HBV and Hev in blood donors with a recognized history of viral hepatitis infection (group A) and in randomly selected blood donors (group B). Data collected in 1989 Group A %

Group B %

Positive for:

N

anti-HAY anti-HBc anti-Hey anti-HAY + anti-HBc anti-HAY + anti-Hey anti-HBc + anti-Hey anti-HAY + anti-HBc + anti-Hey

278 1 0 21 5 0 0

(87.1%) (0.3%) (0.0%) (6.6%) (1.6%) (0.0%) (0.0%)

177 7 0 3 1 0 0

(58.8%) (2.3%) (0.0%) (1.0%) (1.3%) (0.0%) (0.0%)

14

(4.4%)

113

(37.6%)

Negative for antibodies to HAV, HBV and Hev markers

N

Fig. 1 shows the age at which the HAV infection occurred in the 278 donors from group A who were positive for anti-HAV only. One (0.3%) blood donor was positive for anti-HBc only. Group B

The results of control group B are summarized in Table 1. 58.8% of these blood donors were positive for antibodies to HAVonly, 1.0% was positive for antibodies to HAV and HBV, and 0.3 % was positive for antibodies to HAV and Hev. Antibodies to HBV were found in 2.3% The rest of this group of blood donors (37.6%) was completely negative for antibodies to HAV, HBV and Hev. The overall prevalence rate of anti-HAY was found to be 60%. This percentage gives only a crude picture because it is largely affected by the age distribution in the group. Fig. 2 gives a survey of anti-HAY prevalence as a function of age and compares the new 1989 data with our results from 1979 and 1982. When comparing the anti-HAY prevalence data from 1979, 1982 and 1989, the same results was found in the 20 to 24 age group (Fig. 2). In the group born between 1956 and 1960 (age group 20-24 in 1979 and age group 30-34 in 1989), anti-HAY antibody prevalence had increased by 11 % (Fig. 3). A similar increase of anti-HAY antibodies has been observed in the other groups. In the group born between 1951 and 1955 (age in 1979: 25-29, age in 1989: 35-39), prevalence increased by 13%. In the group born between 1946 and 1950 (age in 1979: 30-34, age in 1989: 40-44), prevalence increased by 2%. In the group born between 1941-1945 (age in 1979: 35-39, age in 1989: 45-49), prevalence increased by 3% (Fig. 3).

Discussion and Conclusion The group of blood donors with a clinical history of viral hepatitis accounted for 6.6% of the population investigated. In this group, 87.1 % to 95.3% had a clinically

~

w

o

10

20

30

40

50

0-4

c::::::J 1>1

men

taIaI

women

5-9

10-14

15-19 20-24

25-29

30-34

35-39

40-44

45-49

Fig. 1. Proportional distribution of the age of occurrence of a clinically recognized HAV infection, data collected in 1989.

I

r

I

~

j

%

>50

age

to

~

UJ

Vl

'"

o ::l o ....

t:1

0..-

o

0"

2 '"'" '"5·

5

'"

§:

~

"0

::r: '"

'"'" 8

e-:

o

iT

~

o ......

'"

(')

~

g

'"t:I ....

~

o

20

40

80

80

100

[JJ

20-24

1978

1:1 11182

25-29

Ilm'MJ 1888

31).34

35-38

40-44

Fig. 2. Anti-HAY prevalence among Belgian blood donors as a function of age, Data from 1979, 1982 and 1989.

i

s

45+

age

... ~

'"

;:;...

c

~

r

~

::l

I»

~

~

::l

I»