Experience with the subunit influenza vaccine shows a favourable safety profile. Out of 40 million vaccinations with the subunit vaccine (Influvac) since 1981, only 89 serious signs and symptoms from 65 subjects were reported to the manufacturer (Solvay Duphar, Netherlands).’ Of these adverse events, 8 were related to the respiratory system, including 5 cases of asthma exacerbations. Although we do not know how many of the 40 million vaccine doses were given to asthmatic patients, we may assume that this number is considerable because of specific inclusion of asthmatics in the high-risk patients for whom annual influenza vaccinations are
Chromosomal DNA extracted from strains of V cholerae 01, biotype E)Tor, serotype, )naba, isolated in 1991 from patients with diarrhoea in Ecuador (lanes 1---4) and Bangladesh (lanes
5-9). III-digested chromosomal DNA, hybridised with 32pdeoxycytidine triphosphate labelled 7 5-kb Bam Ht fragment from cloned rRNA gene probe, pKK 3535. Hind
due to El Tor biotype, both Inaba and Ogawa serotypes, in these areas. We have compared 5 strains of Inaba serotypes isolated in June and July, 1991, from this outbreak with 4 strains of Inaba serotype isolated from cases of cholera in Ecuador in April, 1991, to see if any clonal relation existed between the strains causing epidemics in the two distant continents. The strains were examined by Southern blots of Hind III digested chromosomal DNA probed for conserved rRNA genes with a cloned rRNA gene probe, derived from pKK 3535.3 The 4 Ecuadorian strains (figure, lanes 1-4) and the 5 Bangladeshi strains (lanes 5-9) produced identical Hind III cleavage patterns of their rRNA genes, suggesting genetic identity for V cholerae 01 strains causing epidemics in Bangladesh and Ecuador. In a recent report,4 strains of V cholerae 01 from Peru were genetically different from the V cholerae 01 strains that caused disease in the US gulf coast, but were related to strains from Malavi and Truk, which are thought to be part of the expanding seventh pandemic area. Our data lend further support to the notion that the South American cholera outbreak is attributable to the strain of V cholerae 01 that is causing the seventh pandemic and which is continuing to invade new territories. Dr Alfredo Davilo, National Institute of Health,
supplied 4 strains of Inaba serotype. International Centre for Diarrhoeal Disease Research, Bangladesh ICDDR,B, Dhaka 1000, Bangladesh
SHAH M. FARUQUE
1. Centers for Disease Control. Update: cholera outbreak: Peru, Ecuador, and Colombia. MMWR 1991; 40: 225-27. 2. Glass RI, Becker S, Huq MI, et al. Endemic cholera in rural Bangladesh, 1966-1980.
Am J Epidemiol 1982; 116: 959-70. 3. Stull TL, Li Puma JJ, Edlind TD. A broad spectrum probe for molecular epidemiology of bacteria ribosomal RNA. J Infect Dis 1988; 157: 280-86. 4. Wachsmuth IK, Bopp CA, Fields PI, Carrilo C. Difference between toxigenic Vibrio cholerae O1 from South American and US gulf coast. Lancet 1991; 337: 1097-98.
Influenza vaccination in asthma SIR,-Dr Hassan and colleagues (Jan 18, p 194) report exacerbations of asthma in
some of their patients and therefore "do not annual influenza vaccine in stable asthmatics". Although case reports are important in generating hypotheses, they can never be used to prove them. A cause-effect relation between vaccination and aggravation of asthma has not been established, as pointed out in the reply by Dr Ong (Feb 8, p 367). Application of these findings to a whole population group can be hazardous for individual patients who might, therefore, not receive vaccination.
recommended. We agree with Hassan et al about the favourable side-effect profile of influenza subunit vaccine. In clinical studies of 2038 healthy volunteers, 695 (34%) reported local reactions (mainly pain at site of the injection) and 303 (15%) systemic reactions (mainly headache). In 1931 (95%) subjects, the reported reactions did not cause inconvenience. In a placebo-controlled study in elderly subjects, Margolis et aP found no significant differences between trivalent influenza split vaccine and placebo with respect to any local or systemic reaction apart from a sore arm (20%). Despite occasional serious adverse events, such as those reported by Hassan et al, our data demonstrate the safety and tolerance of the influenza subunit vaccine and do not justify Hassan and colleagues’ statement that "influenza vaccines have many side-effects". Despite the case reports by these workers, the established safety of influenza vaccines justifies present public health recommendations3.4 that at least 80% of high-risk patients, including asthmatics, should be immunised annually to reduce the risks of influenza-associated
Drug Experience Unit, Solvay Duphar, 1380 DA Weesp, Netherlands
A. M. PALACHE J. W. VD VELDEN
1. Palache AM. Influenza vaccination. The effect of dose and age on the antibody response: a methodological evaluation of serological vaccination studies. Erasmus University, Rotterdam, Netherlands, PhD thesis, 1991. 2. Margolis KL, Nichol KL, Poland GA, Pluhar RE. Frequency of adverse reactions to influenza vaccine in the elderly: a randomized, placebo-controlled trial. JAMA
1990; 254: 1139-41. 3. Advisory Committee on Influenza Prevention. MMWR 1987; 36: 373-87. 4. Calman KC. Influenza immunisation. London: Department of Health, PL/CMO(91) 13; Oct 8, 1991.
Epoprostenol infusions in thrombotic microangiopathy of pregnancy haemolytic-uraemic syndrome (HUS) and thrombocytopenic purpura (TTP) are thrombotic microangiopathies in which there is extensive platelet aggregation within the microcirculation. The success of plasma exchange suggests a potent platelet aggregatory factor, and anti-platelet agents might be expected to be of benefit. We report a patient who was much improved after infusion of epoprostenol (prostacyclin). A 35-year-old woman presented in her second pregnancy. Eclampsia in her first pregnancy precipitated delivery by caesarean section. The second pregnancy progressed without incident up to 25 weeks, when she noticed severe ankle swelling. Her blood pressure (BP) was 150/ 100 mm Hg and she had 2 + proteinuria. SiR,-Both
She was admitted for bed rest. Ultrasound scan revealed a small-for-dates fetus and normal-sized kidneys. Her BP did not settle so she was started on methyldopa and the anti-platelet agent sulphinpyrazone. Despite this, her BP remained above 110 mm Hg diastolic. Her haemoglobin (Hb) fell to 108 g/dl, platelets dropped to 87 x 109/l, fibrinogen degradation products (FDP) were 10-40 Jlgjml, and fragmented red blood cells were seen on the blood film. Thrombotic microangiopathy superimposed on pregnancyinduced hypertension was diagnosed, and on day 6 she was started on an infusion of epoprostenol 2 ng/kg per min, which was increased to 20 ng/kg over 24 h. The infusion appeared to control her BP and her Hb and platelet count rose (figure). The infusion was stopped and she went home for 2 days. On her return her diastolic BP had risen to 100 mm Hg and her platelet count had fallen; both measures improved when epoprostenol was restarted. An ultrasound scan in the 28th week demonstrated oligohydramnios and a fetal size compatible with 25-26 weeks. A girl was delivered by caesarean