New Japanese rubella vaccine: comparative trials

Live attenuated vaccine efficacy six months after intravenous immunoglobulin therapy for Kawasaki disease

BACKGROUND

Due to the presence of maternal passive antibodies, the measles vaccine is ineffective if administered before age 12-15 months. The optimal timing for administering a live attenuated vaccine (LAV) after intravenous immunoglobulin therapy (IVIG) for Kawasaki disease (KD) has not been fully investigated. The recommended interval between vaccination and IVIG therapy for KD differs by country. The present study aimed to evaluate efficacy of LAV six months after IVIG therapy for KD in Japan.

METHODS

The present, single-arm, prospective, interventional study included patients aged 6 months or older with no medical history of measles, rubella, varicella or mumps or vaccinations against these diseases. The subjects received these vaccinations for the first time at six months after IVIG therapy. Virus-specific IgG levels for each virus measured by EIA was examined at nine months after IVIG therapy. If the results were negative, the subjects received a booster vaccination at 12 months after IVIG therapy. The primary outcome was the prevalence of positivity for antibodies after the initial and booster vaccinations.

RESULTS

The present study enrolled 32 subjects, 31% of whom were female, with an average age of 10.8 (standard deviation 2.8) months at IVIG therapy. At six months after IVIG therapy, 9% and 6% of the subjects were seropositive for measles and varicella titers, respectively, but were seronegative for the mumps and rubella titers. The seroconversion rate for measles, mumps, rubella, and varicella after the initial vaccination was 88%, 6%, 78%, and 16%, respectively. The seroconversion rate after a booster vaccination was 100% for measles and rubella, 97% for mumps, and 77% for varicella.

CONCLUSIONS

The seroconversion rate was low for LAV at six months after a single dose of IVIG for KD, but seroconversion was achievable with a booster vaccination at 12 months.

CLINICAL TRIAL REGISTRATION

UMIN-CTR, UMIN000007174, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000008452.

Chapter 9 Infections caused by rubella, reoviridae, retro, Norwalk and ronaviruses

This chapter focuses on infections caused by rubella, reoviridae, retro, Norwalk and coronaviruses. High incidence of acute gastroenteritis caused by rotaviruses calls for prophylactic and therapeutic measures. Although no vaccine is presently available, it seems likely that vaccines will be developed in the next few years. There are also several rotavirus enzymes useful as targets for antiviral drugs. However, no antiviral drugs have shown therapeutic effects against rotavirus infections. The newly discovered human retrovirus (HTLV) has not yet been investigated in such detail as to predict the usefulness of vaccine or antiviral drugs. Several compounds are known to inhibit other retrovirus enzymes but the implication of this for chemotherapy of HTLV infection is unknown at present. The possibility and need for vaccination or chemotherapy against Norwalk virus and related agents is unclear. Very little work has been carried out to date with human coronaviruses, either from the point of view of vaccine development or specific antivirals. Both approaches may be usefully investigated in the future. Genetic cloning may be particularly useful for development of inactivated vaccines because the virus itself would be difficult to replicate and purify in large quantities for conventional vaccines.

Mutations of rubella virus vaccine TO-336 strain occurred in the attenuation process of wild progenitor virus

The sequences of the genomes in the TO-336 vaccine strain (TO-336vac) of rubella virus and its wild progenitor virus (TO-336wt) have been determined and compared with each other. There were 21 differences in the nucleotide sequences between the TO-336vac and the TO-336wt: 13 in the nonstructural protein open reading frame (NSP-ORF), five in the structural protein open reading frame (SP-ORF) and three in the untranslated regions (UTRs) (one in each three UTRs). These mutations resulted in amino acid substitutions at ten residues. Of the ten substitutions, eight were in NSP-ORF and two were in the SP-ORF. Of the eight substitutions in NSP-ORF, four (amino acids (aa) 320, 501, 573 and 704) were in the regions of unknown function, two (aa 1154 and 1159) were within the protease motif, and two (aa 1351 and 1559) were within the helicase motif. Both of the two residues (aa 890 and 954) in the SP-ORF were within the E1 gene. The predicted second structure of the 5'UTR of the TO-336vac was identical to that of TO-336wt. Comparing the TO-336 sequences with other four strains, Therien and M33 (wild viruses), and RA27/3 and Cendehill (vaccine viruses), the mutations responsible for attenuation are thought to differ with each vaccine strain. This is the first report of sequencing in a pair of live attenuated rubella vaccines and their wild-type parent.

Mapping of genetic determinants of rubella virus associated with growth in joint tissue

Rubella virus (RV) strains vary in their abilities to replicate and persist in cell cultures derived from human joint tissue (synovial cells [SC]), and this arthrotropism appears to be linked to their association with joint symptoms in vivo. In order to map the genetic determinants of arthrotropism, an infectious clone of the Cendehill vaccine strain of RV was constructed, as well as two chimeric clones containing cDNAs from both Cendehill and Therien (wild-type) strains. Replacement of the entire structural gene region of Therien in the infectious clone pROBO302 with the corresponding region of Cendehill did not affect growth in SC. A further observation that Cendehill bound equally well to SC and the permissive Vero cell line indicated that restriction was not at the level of receptor binding, a function of the envelope proteins. Mutations that affected growth in joint cells were mapped to two locations in the nonstructural gene region. The first of these (nucleotides 2803 and 6416) resulted in a 10-fold decrease in yield of progeny virus from SC. This region contained five mutations, at nucleotides 2829, 3060, 3164, and 3528 (near the carboxy terminus of P150 where the protease domain is located) and at nucleotide 4350 in p90. Further substitution of the sequence representing nucleotides 1 to 2803 to give a complete Cendehill infectious clone restricted growth in SC by a further 100-fold to less than 10 PFU/ml. This region contains three mutations, at nucleotides 34, 37, and 55, within the 5' stem-loop structure. In conclusion, the Cendehill-specific mutations believed to be determinants of joint cell growth are located in two regions, the 5' nontranslated region and in a sequence that encodes the carboxy-terminal region of p150 extending into the helicase domain of p90.

Rubella virus and chronic joint disease: is there an association?

Synovial fluid samples and/or biopsies from 79 patients with various chronic inflammatory joint diseases or traumatic joint injury were tested for rubella virus (RV) in order to confirm or refute results from other studies that suggested RV as a cause of chronic inflammatory joint disease. Sixty-eight of the 72 patients tested had RV antibodies. RV RNA was detected by reverse transcription-PCR in the synovial fluid cells from two patients. RV was also isolated by cell culture from the synovial fluid of one of these two patients. This patient was a 42-year-old female with common variable immune deficiency and Mycoplasma hominis arthritis, while the other was a 68-year-old female with rheumatoid arthritis. While these results fail to confirm that RV is associated with chronic inflammatory joint disease, they suggest that RV may persist within a joint and be reactivated when cell-mediated immunity is suppressed.

La autoantigen binding to a 5' cis-element of rubella virus RNA correlates with element function in vivo

Rubella virus genomic RNA contains a 5' stem-loop (5'(+) SL) which is required for efficient translation and replication. The La autoantigen previously was shown to bind this RNA sequence in vitro. Results reported here demonstrate that this cellular RNA-binding protein binds to the RV 5' SL RNA with sufficient specificity for the binding to occur in the presence of excess total cellular RNA. Further, the affinity of purified La for the RV sequence is similar to its affinity for known cellular substrates. To address the functional significance of La binding, mutant forms of the RV 5'(+) SL were analysed which bind La weaker or stronger than the native form. These three forms of the RV 5' SL were incorporated into RV-luciferase constructs which expressed luciferase activity in transient transfection. The level of expression from each construct correlated with the ability of its RV sequence to bind La. The detection of La/RV RNA complexes in infected cells further supported the physiological relevance of this interaction. Possible implications of autoantigen La interaction with RV RNA for rubella virus pathology and vaccine associated adverse reactions are discussed.

Infection-related arthritis

Postinfection arthritis represents a significant portion of the referrals to pediatric rheumatology centers, particularly in the United States. Many viral and common bacterial infections can be associated with arthritis, and their recognition can sometimes be difficult on a clinical basis. In patients with acute onset of arthritis, the clinician should actively seek epidemiologic, clinical, or laboratory evidence of infection. Diagnostic tests should be used rationally and results interpreted carefully. Some infections, once recognized, require antibiotic treatment, but in most cases anti-inflammatory therapy is successful in treating articular symptoms.

Autoantigens interact with cis-acting elements of rubella virus RNA

Rubella virus (RV) infections in adult women can be associated with acute and chronic arthritic symptoms. In many autoimmune individuals, antibodies are found targeting endogenous proteins, called autoantigens, contained in ribonucleoprotein complexes (RNPs). In order to understand the molecular mechanisms involved in the RV-associated pathology, we investigated the nature of cellular factors binding RV RNA and whether such RNPs were recognized by antibodies in infected individuals. Previously, we noted that cellular proteins associated with the RV 5'(+) stem-loop (SL) RNA are recognized by serum with Ro reactivity. To better understand the nature of the autoantigens binding RV cis-acting elements, serum samples from individuals with various autoimmune diseases were tested for their ability to immunoprecipitate RNPs containing labeled RV RNAs. A subset of serum samples recognizing autoantigen La, or Ro and La, immunoprecipitated both the RV 5'(+)SL and 3'(+)SL RNA-protein complexes. Autoantigens binding the RV 5'(+)SL and 3'(+)SL RNAs differed in molecular mass, specificities for respective RNA binding substrates, and sensitivity to alkaline phosphatase treatment. The La autoantigen was found to interact with the RV 5'(+)SL RNA as determined by immunological techniques and binding reactions with mixtures containing recombinant La protein. To test whether there is a correlation between La binding to an RV RNA element and the appearance of an anti-La response, we measured anti-La titers in RV-infected individuals. Significant anti-La activity was detected in approximately one-third of RV-infected individuals 2 years postinfection.

Rubella vaccines: past, present and future

The association between rubella in pregnancy and congenital anomalies was first reported 50 years ago, by N. McAlister Gregg, an Australian ophthalmologist [1]. During the next 20 years his findings were confirmed by others (reviewed in [2]). However, the first reports of the isolation of rubella virus in cell cultures and development of tests for neutralizing antibodies were not published until 1962 [3, 4]. Subsequent studies conducted in the UK and North America during a pandemic of rubella in 1963–4, were therefore able to make a more accurate estimate of the risks of maternal rubella at different stages of pregnancy. It was estimated that about 30000 rubella-damaged babies were born in the USA alone in 1963–4 [5]. This emphasized the importance of developing a vaccine to prevent infection in pregnancy and thereby, the birth of babies with rubella-induced congenital defects.

Improvement in potency assay of measles-mumps-rubella trivalent vaccine: interference between components and measures for its elimination

In the potency assay of trivalent measles-mumps-rubella (MMR) vaccine by the immunocytochemical focus assay reported previously (Fukuda et al., 1987), development of rubella foci in RK13 cells was inhibited in the presence of a large excess of mumps component, resulting in an underestimation of the titre of the rubella component. When RK13 cells are infected with the mixture of mumps and rubella viruses, mumps virus interfered with the growth of rubella virus. Interference was mediated most likely by interferon induced by mumps virus. The interference was eliminated by a partial neutralization of mumps component by the addition of anti-mumps serum to the inoculum to RK13 cells. Improved method of potency assay of MMR vaccine incorporating the above measures and other modifications are described.

Specific antibody patterns over a two-year period after rubella immunization with RA 27/3 live attenuated vaccine

Screening for rubella antibodies was carried out on 1557 schoolgirls aged 9-20. Of seronegative subjects 70% (442/631) were immunized with RA 27/3 rubella vaccine and some of the vaccinees underwent a serological and clinical follow-up over a two year period. Adverse reactions occurred in 27% of vaccinees, usually 1-2 weeks after immunization; late reactions were never observed. The vaccine-induced seroconversion rate evaluated at 4-5 weeks after immunization was 99.7%. Both one and two years after immunization the seropositivity rate of vaccinees was 100%. The maximum geometric mean antibody titre (GMT) was observed at 4-5 weeks after vaccination and a significant GMT decrease was evident on both the following annual controls. Specific antibody patterns in vaccinees were highly variable and in a small number of subjects a remarkable antibody titre decrease was noticed.

Factors associated with clinical reactions to rubella vaccination in women

Two types of rubella vaccine were given to 272 seronegative healthy Japanese adult women. Clinical and laboratory studies on clinical reaction after vaccination were carried out on HI antibody response, HLA types, basal body temperature (BBT), menstrual cycles and serum progesterone levels of vaccinees. Clinical reactions were not associated with HLA types of vaccinees, but arthropathy occurred significantly more often in women vaccinated at the progestational stage than in women vaccinated at the estrogenic stage.

Rubella-associated arthritis. I. Comparative study of joint manifestations associated with natural rubella infection and RA 27/3 rubella immunisation

Joint manifestations observed during the course of a prospective RA 27/3 rubella immunisation trial were compared with those observed during an intercurrent wild rubella epidemic in an outlying community. Among 44 rubella haemagglutination inhibition (HAI) negative females ranging in age from 17 to 33 years who received rubella vaccine, six (13.6%) developed acute polyarticular arthritis within two to four weeks postvaccine and two (4.5%) had continuing or recurrent arthropathy lasting longer than 18 months. In contrast, among 23 females ranging in age from 11 to 39 years undergoing wild rubella infection, 12 (52.2%) developed acute polyarticular arthritis and seven (30.4%) had recurrent arthropathy 18 months postinfection. Among 23 males ranging in age from 13 to 54 years undergoing wild rubella infection, only two (8.7%) developed acute arthritis and both individuals had continuing joint manifestations 18 months postinfection. Wild rubella infection in adult populations is associated with a higher incidence, increased severity, and more prolonged duration of joint manifestations than is seen after RA 27/3 rubella immunisation.

Prospective immunological assessment of arthritis induced by rubella vaccine

A prospective study was carried out to correlate the development of joint symptoms after rubella immunization with pre- and post-immunization rubella-specific immunological responses. Arthralgia or arthritis or both occurred in 10 of 37 adult female volunteers at a mean time of 17.0 days after immunization with the RA 27/3 rubella vaccine. All individuals studied before immunization were seronegative for rubella by either the hemagglutination inhibition or the single radial hemolysis technique. In contrast, rubella enzyme-linked immunosorbent assay or lymphoproliferative responses or both were positive in 27 of 37 (73%) individuals tested before receiving the vaccine. Rubella enzyme-linked immuno-sorbent assays carried out before immunization were positive at high levels (mean E = 0.536) in four individuals who developed recurrent episodes of arthritis after administration of the vaccine while remaining at low levels preimmunization in subjects who developed transient arthralgia (E = 0.238) or no joint manifestations at all (E = 0.288). These data provide preliminary evidence suggesting that rubella vaccine-associated arthritis may occur as a consequence of secondary, rather than primary, infection with rubella virus and that the presence of circulating, nonneutralizing rubella antibody may enhance the development or severity (or both) of the associated postinfection joint manifestations. Assessment of rubella hemagglutination inhibition, hemagglutination inhibition (immunoglobulin M), and enzyme-linked immunosorbent assay serological responses at 6 weeks and 6 months post-immunization revealed no significant differences between patients who developed and those who did not develop joint manifestations. Rubella lymphoproliferative responses were elevated at 6 weeks post-immunization in the group developing arthralgia or arthritis or both, with no difference between the groups observed at 6 months post-immunization.

Rubella vaccination: persistence of antibodies for up to 16 years

Sera from 123 volunteers vaccinated six to 16 years previously with one of four rubella vaccines (Cendehill, RA27/3, HPV77-DE5, and To-336) were tested for rubella antibodies by single radial haemolysis and radioimmunoassay. By radioimmunoassay 110 (89.4%) of the vaccinees had antibody concentrations greater than the minimum immune titre (that is, greater than 15,000 IU/1), 11 (8.9%) were seropositive but had concentrations less than or equal to 15,000 IU/1, and two (1.6%) were seronegative. Eight (6.5%) were seronegative by single radial haemolysis, of whom five had received Cendehill vaccine. Six to eight years after vaccination subjects who had received Cendehill vaccine had the lowest geometric mean titre of antibody by radioimmunoassay while the subjects who had received HPV77-DE5 vaccine had the highest. Although antibody concentrations less than or equal to 15,000 IU/1 were not detected among subjects given RA27/3 vaccine six to eight years previously, such low levels were detected in two (15.4%) vaccinated 11-16 years previously. These results emphasise the importance of long-term surveillance programmes so that vaccination policies may be reviewed.

Persistent rubella infection and rubella-associated arthritis

Rubella virus has been isolated from peripheral blood lymphocytes in six out of seven women with rubella-associated arthritis. The arthritis occurred after natural infection (one case) or immunisation with HPV 77 DES vaccine (six cases) and had been present for up to 6 years. The identification of rubella virus was confirmed by plaque/microfocus reduction in the presence of anti-rubella antiserum, and by immunoprecipitation of rubella virus antigens and their analysis on polyacrylamide gels. These women with rubella virus in their lymphocytes did not have abnormal serum antibody levels, but a standard lymphoproliferative assay showed that they had strong cell-mediated immune responses to rubella virus antigens.

Rubella immunity by four different techniques: results of challenge studies

When 42 sera with low or inconsistent levels of haemagglutination-inhibiting (HAI) antibodies were tested by single radial haemolysis (SRH) radioimmunoassay (RIA), and enzyme-linked immunoassay (ELISA), RIA was shown to be the most reliable test for detecting low levels of antibody. SRH, however, was found to be an acceptable alternative screening test for rubella antibodies and was more reliable than HAI. Although SRH plates prepared in our own laboratory failed to detect antibodies in six sera, in five of the six, antibodies were only at a low level (RIA titre 1:20-1:80). OriVir plates (Orion Diagnostica, Finland) failed to detect low levels of antibody in only three sera. There were six (14.3%) sera which were false positives in the HAI test. These women were shown to be seronegative by radioimmunoassay and, when three of these six volunteers were vaccinated, they developed a typical primary immune response which resembled that developed by 43 seronegative women following vaccination. Fifteen of the young women with consistently low HAI titres and one woman who was seronegative by HAI but seropositive by RIA and ELISA were subsequently vaccinated. Six (37.5%) of these women showed no significant rise in titre by any of the tests employed, while ten had a significant rise in titre, detected by at least one test, with a low level of rubella-specific IgM detectable in one.

HLA antigens and responses to rubella vaccination

Attempts were made to correlate virus excretion, joint symptoms and antibody response with human leukocyte antigens (HLA) in seronegative adult women given attenuated rubella vaccine. No association was shown between HLA antigens of the A and B loci and excretion of either high or low titres of RA27/3 vaccine among 26 volunteers. However, virus excretion was influenced by such factors as the time of day at which specimens were collected and the method of virus isolation. Our study therefore failed to confirm the hypothesis that certain persons are good 'spreaders' of rubella virus and that this capacity is associated with HLA-A1 and B8. The study of joint symptoms following vaccination with Cendehill, HPV77.DE-5, RA27/3 or To-336 vaccines showed no association between such symptoms and HLA antigens. However, joint symptoms occurred within 7 days of the onset of menstruation in 33 of 47 (70%) vaccinees (P less than 0.01) and it is therefore suggested that hormonal factors must play a role. No association between HLA antigens and haemagglutination inhibition (HAI) antibody titres, 8 weeks after vaccination with RA27/3, was found amongst 34 volunteers.

Antibody titres in women six to eight years after the administration of RA2713 and Cendehill rubella vaccines

Titres of haemagglutination-inhibiting antibody have been measured repeatedly in young women during a period of 6-8 years after the administration of RA27/3 and Cendehill attenuated rubella vaccines. Mean antibody titres were initially 217 after RA27/3 and 159 after Cendehill, but the difference diminished after the first year. Antibody titres were subsequently well maintained in both groups and did not reveal any need for regular revaccination. Mean titres in the Cendehill group were partly maintained by symptomless reinfection which was commoner after Cendehill than after RA27/3. Significant falls in titre were equally common after both vaccines, but low titres of 30 or less were more frequent in subjects who had received Cendehill. Mean neutralizing antibody titres were initially 15.4 after RA27/3 vaccine and 9 after Cendehill. Titres remained higher after RA27/3 for 3 years, but the difference then diminished and became insignificant during the fifth year. Revaccination of women with low antibody titres produced significant increases in 69% of subjects when standard RA27/3 vaccine was used; a special preparation of RA27/3 of higher potency produced a similar number of rises (70%) but elicited higher titres and might occasionally be useful for revaccinating women who are likely to come into contact with rubella. Challenge with RA27/3 vaccine produced weaker responses in women who had experienced natural infection than in those whose antibody was vaccine-induced. Rises in antibody titre after revaccination consisted mainly of IgG, but traces of IgM antibody were detected in one vaccinee who had recently experienced natural reinfection and in 1 woman with naturally acquired antibody who had been challenged with high titre RA27/3 vaccine.

Unresolved issues in the first five years of the rubella immunization program

Despite extensive use of atttenuated rubella vaccine during the past five years, the degree of fetal risk in susceptible women inoculated early in pregnancy is still an unresolved issue. Although there is considerable evidence of chronic vaccine virus infection of the products of gestation in aborted fetuses, congenital defects have not yet been reported in the newborn infants of susceptible vaccinated pregnant women. The normal findings in the newborn infant can be misleading with respect to the safety of the vaccines in early pregnancy, because they represent only a small selected group of reported cases. The immediate need is for more complete reporting of all relevant cases wherever they occur in order to determine without many more years of delay whether the fetal risk has public health significance or is so low as to be of negligible importance.

Role of rubella in congenital malformations in India

In the present study rubella HI antibodies were determined in cases of congenital malformation and bad obstetric history to determine the role of rubella in such cases in India, as it has been reported to be rare in Japan in contrast to Western countries. The incidence of antibodies was statistically significant in cases of congenital eye, C.N.S., visceral and miscellaneous malformations and cases of spontaneous abortion and still-birth compared with controls of matching age groups. This is further supported by the demonstration of IgM antibodies in seven cases of congenital malformations and ten cases of spontaneous abortion. Our findings show that congenital rubella is not rare in India.

Detection of rubella-specific serum IgG and IgA and nasopharyngeal IgA responses using a radioactive single radial immunodiffusion technique

A radioactive, single radial immunodiffusion technique (RSRID) employing 125I-labelled antiglobulins, was developed to determine rubella-specific serum IgG and IgA and nasopharyngeal IgA antibody responses following both naturally acquired rubella and vaccination with four attenuated vaccines. Rubella-specific IgG antibodies developed in parallel with haemagglutination inhibiting (HAI) antibodies and both persisted for at least a year in all cases of naturally acquired and vaccine induced infection. However, the RSRID test detected rises in titre in all of five volunteers challenged intranasally with RA27/3, whereas only one volunteer showed a rise by HAI. Serum IgA antibodies generally persisted for at least a year following naturally acquired infection but rubella vaccines induced variable responses. Thus, following administration of RA27/3 and To-336 vaccines, rubella-specific IgA usually persisted for a year, whereas Cendehill vaccine failed to induce a detectable response. Rubella-specific nasopharyngeal IgA was detected in all five patients following naturally acquired infection and was still present in the only two patients tested a year after infection. These antibodies were detected in fourteen of twenty-three vaccinees at 3 weeks, but persisted for a year in only two vaccinees, both of whom were given RA27/3 intranasally.

Rubella-specific serum and nasopharygeal immunoglobulin responses following naturally acquired and vaccine-induced infection. Prolonged persistence of virus-specific IgM

Rubella-specific immunoglobulin responses in sera and nasopharyngeal secretions were compared in groups of adult females who had experienced naturally acquired rubella or infection induced by Cendehill, HPV77.DE-5, RA27/3 (subcutaneously and intranasally), and To-336 vaccines. Serum IgG and IgA and nasopharyngeal IgA responses after vaccination by RA27/3 intranasally most closely resembled those induced by naturally acquired infection. However, the other vaccines failed to induce a persistent local IgA response. Levels of local antibody induced by HPV77.DE-5 were especially poor. Virus-specific IgM was detected for prolonged periods. The highest levels and the most persistent response followed vaccination by HPV77.DE-5, four of five volunteers still having rubella-specific IgM at 1 year. Virus-specific IgM persisted for 6 months in seventeen of twenty-five (68%) and for a year in nine of twenty-four (38%) vaccinees. It was still present in four of nine (44%) naturally infected patients at a year.