Analysis of safety data in children after receiving two doses of ProQuad® (MMRV)

Combined measles-mumps-rubella-varicella vaccine and febrile convulsions: the risk considered in the broad context

INTRODUCTION

Studies on quadrivalent measles, mumps, rubella, and varicella (MMRV) vaccines have indicated a twofold increased relative risk of febrile convulsion (FC) after the first dose compared to MMR and V administered at the same medical visit (MMR+V).

AREAS COVERED

This narrative review contextualizes FC occurrence after the first MMRV vaccine dose from a clinical perspective and outlines approaches to attenuate FC occurrence post-vaccination.

EXPERT OPINION

While the relative FC risk increases after the first dose of MMRV compared to MMR+V vaccine in measles-naïve infants, the attributable risk is low versus the overall FC risk in the pediatric population triggered by other causes, like natural exposure to pathogens or routine vaccination. No increased risk of FC has been reported after MMRV co-administration with other routine vaccines compared to MMRV alone. Based on our findings and considering the MMRV vaccination benefits (fewer injections, higher coverage, better vaccination compliance), the overall benefit-risk profile of MMRV vaccine is considered to remain positive. Potential occurrence of FC in predisposed children (e.g. with personal/family history of FC) may be attenuated if they receive MMR+V instead of MMRV as the first dose. It is also important to monitor vaccinees for fever during the first 2 weeks post-vaccination.

Immunogenicity and Safety of a Booster Dose of Live Attenuated Varicella Vaccine, and Immune Persistence of a Primary Dose for Children Aged 2 to 6 Years

Aim: To evaluate the immunogenicity and safety of a booster dose of live attenuated varicella vaccine (VarV) manufactured by Sinovac (Dalian) Vaccine Technology Co. Ltd., and the immune persistence of a primary dose in 2- to 6-year-old children. Methods: A phase IV, open-label study was conducted in China. Children previously vaccinated with a single dose of VarV at 1~3 years old received one dose of homologous VarV in the first year, the second year, or the third year after the primary immunization as booster immunization. Immune persistence was evaluated in an immune persistence analysis set, while immunogenicity was evaluated in a per-protocol analysis set, and safety was evaluated in a safety analysis set. The primary endpoint was the seropositive rate and the seroconversion rate of VarV antibody. The trial was registered at ClinicalTrials.gov (NCT02981836). Results: From July 2018 to August 2020, a total of 849 vaccinated children received the booster vaccination of VarV, one booster dose for each child (301 vaccinated in the first year after primary immunization (Group 1), 276 vaccinated in the second year after primary immunization (Group 2), 272 vaccinated in the third year after primary immunization (Group 3)). The seropositive rates were 99.34%, 97.83%, and 98.16% in Groups 1–3, with GMTs of 1:22.56, 1:18.49, and 1:18.45, respectively. Thirty days after the vaccine booster dose, the seropositive rates of the three groups were all 100% and the seroconversion rates were 52.54%, 67.46%, and 66.67%, with GMTs of 1:68.49, 1:76.32 and 1:78.34, respectively. The seroconversion rates in Groups 2 and 3 were both higher than that in Group 1 (p = 0.0005 and p = 0.0008). The overall incidence of adverse reactions was 7.77%, with 7.64%, 8.33%, and 7.35% in Groups 1, 2, and 3, respectively. The main symptom among adverse reactions was fever, the incidence of which ranged from 5.07% to 6.64% in each group, and no vaccine-related serious adverse events occurred. Conclusions: VarV had good immune persistence in 1~3 years after primary immunization. A vaccine booster dose for children aged 1~3 years after primary immunization recalled specific immune response to varicella-zoster virus, with no safety concerns increased.

Second dose of measles-mumps-rubella-varicella vaccine (MMRV) and the risk of febrile convulsions

INTRODUCTION

Studies have shown an increased risk of febrile convulsions (FC) after first immunization with the quadrivalent measles-mumps-rubella-varicella vaccine (MMRV) compared to a first dose of measles-mumps-rubella vaccine (MMR) only or in combination with separately administered varicella vaccine (MMR + V). Therefore, it is recommended to give MMR + V at first dose and MMRV or MMR + V at second dose. Little is known on the risk of FC after MMRV at second dose, especially whether the risk depends on age, sex, history of FC or type of first dose vaccine.

METHODS

A retrospective cohort study using claims data from the German Pharmacoepidemiological Research database (GePaRD) was performed in children born between January 1st, 2004 and October 31st, 2015 who received two doses of MMRV, MMR + V or MMR. Cases were defined as hospitalization with a diagnosis of FC without neurological conditions coded as main discharge diagnosis. Unadjusted and adjusted odds ratios (OR) with 95% confidence intevals (CIs) were calculated to compare the risk of FC. Stratified analyses were performed to examine potential effect modification by age, sex, history of FC or type of first dose vaccine.

RESULTS

In the first 30 days after second dose vaccination, 464 FCs were observed in a cohort of 528,639 children with a median age of 17 months. After adjustment for potential confounders, the adjusted OR for FC in the 30 days after vaccination was 1.25 (95% CI 0.67-2.30) for MMRV compared to MMR + V and 1.04 (0.82-1.32) for MMRV compared to MMR. History of FC was the most important risk factor with an OR of 36.26 (29.30-44.89). We found no effect modification by age, sex, history of FC, or type of first dose vaccine.

CONCLUSION

Use of MMRV at second dose is not associated with an increased risk of FC compared to MMR + V or MMR, irrespective of age, sex, history of FC, or type of first dose vaccine.

Adverse events following measles-mumps-rubella-varicella vaccine: an independent perspective on Italian pharmacovigilance data

Vaccine surveillance programs are crucial for the analysis of the vaccine’s safety profile and the guidance of health policies. The Epidemiological Observatory of the Italian Apulia Region carried out an active surveillance program of adverse effects following immunization (AEFI) after the first dose of the measles-mumps-rubella-varicella (MMRV) vaccine, finding 462 AEFIs per 1000 doses, with 11% rated serious. Applying the World Health Organization (WHO) causality assessment algorithm, 38 serious AEFIs/1000 enrolled were classified as ‘consistent causal associations’ with MMRV immunization. Severe hyperpyrexia, neurological symptoms and gastrointestinal diseases occurred in 38, 20 and 15 cases/1000 enrolled, respectively. A projection of such AEFIs in an Italian birth cohort would give tens of thousands of serious AEFIs. These incidence data are much greater than the incidence of serious AEFIs reported by the Italian Medicines Agency (AIFA) for years 2017 and 2018, mainly based on passive (or mixed) pharmacovigilance. In a previous epidemiological study in the same Italian Region, during an eight year passive surveillance, the reporting rate of serious AEFI was 0.06/1000 doses, and no cases of febrile seizures were detected applying the WHO algorithm. Taken together, the data suggest that passive pharmacovigilance is utterly inadequate to document the real incidence of serious AEFIs and that current methods of assessing causality may be questioned. Active surveillance programs are required in representative population samples, with results presented separately from those of spontaneous reporting, and causality assessment should be performed carefully and using a correct technique for AEFIs presenting as complex and multifactorial diseases, like those with serious neurologic disorders.

Adverse events following measles-mumps-rubella-varicella vaccine: an independent perspective on Italian pharmacovigilance data

Vaccine surveillance programs are crucial for the analysis of the vaccine’s safety profile and the guidance of health policies. The Epidemiological Observatory of the Italian Apulia Region carried out an active surveillance program of adverse effects following immunization (AEFI) after the first dose of the measles-mumps-rubella-varicella (MMRV) vaccine, finding 462 AEFIs per 1000 doses, with 11% rated serious. Applying the World Health Organization (WHO) causality assessment algorithm, 38 serious AEFIs/1000 enrolled were classified as ‘consistent causal associations’ with MMRV immunization. Severe hyperpyrexia, neurological symptoms and gastrointestinal diseases occurred in 38, 20 and 15 cases/1000 enrolled, respectively. A projection of such AEFIs in an Italian birth cohort would give tens of thousands of serious AEFIs. These incidence data are much greater than the incidence of serious AEFIs reported by the Italian Medicines Agency (AIFA) for years 2017 and 2018, mainly based on passive (or mixed) pharmacovigilance. In a previous epidemiological study in the same Italian Region, during an eight year passive surveillance, the reporting rate of serious AEFI was 0.06/1000 doses, and no cases of febrile seizures were detected applying the WHO algorithm. Taken together, the data suggest that passive pharmacovigilance is utterly inadequate to document the real incidence of serious AEFIs and that current methods of assessing causality may be questioned. Active surveillance programs are required in representative population samples, with results presented separately from those of spontaneous reporting, and causality assessment should be performed carefully and using a correct technique for AEFIs presenting as complex and multifactorial diseases, like those with serious neurologic disorders.

Post-marketing surveillance of adverse events following measles, mumps, rubella and varicella (MMRV) vaccine: retrospecive study in apulia region (ITALY), 2009-2017

Since 2006, some Italian Regions introduced the active offer of measles, mumps, rubella, and varicella (MMRV) vaccine for all newborns during the second years of life. In 2011, Italian Drug Authority (AIFA) recommended the discontinuation of the MMRV use for an increased risk of febrile seizures following vaccination; furthermore, some Regions (such as Apulia, that introduced MMRV offer in 2009) chose to continue the use of MMRV and Ministry of Health recommended to guarantee supplemental monitoring of safety of the vaccine. In Italy, the surveillance of Adverse Events following immunization (AEFIs) is currently carried out by AIFA and Regional Health Authorities; this paper aims to summarize the results of MMRV-vaccine surveillance of AEFIs program carried out in Apulia. From the AIFA database, we selected MMRV AEFIs that occurred in Apulia (about 4,000,000 inhabitants) from 2009 to 2017. For serious AEFIs, we applied the WHO causality assessment algorithm, using for cases hospitalized information from individual medical records. In the 8 years of observation, 155 MMRV-AEFIs (reporting rate: 37.9×100,000 doses) occurred of which 26 were classified as serious (6.3×100,000 doses) and 22 led to hospitalization. Performing causality assessment, for 10 the classification was "consistent causal association to immunization" (reporting rate: 2.4×100000 doses), for 2 indeterminate, for 13 "inconsistent causal association to immunization" and for 1 not-classifiable. No case of febrile seizure resulted consistent to vaccination. All consistent serious AEFIs were completely resolved at subsequent follow-up.

Adverse Events Following Measles-Mumps-Rubella-Varicella Vaccination and the Case of Seizures: A Post Marketing Active Surveillance in Puglia Italian Region, 2017-2018

Since 2012, the Italian Ministry of Health has recommended to improve the surveillance of adverse events following the measles-mumps-rubella-varicella (MMRV) tetravalent vaccine that was provided in the official immunization schedule of some Italian regions for children during the second year of life. This recommendation was based on data from some surveys that showed an additional risk of seizure following the administration of this vaccine. Responding to the Ministry commitment, the Puglia Region launched, from May 2017 to November 2018, a post-marketing active surveillance program of adverse events following MMRV immunization (AEFIs). Immunized children (second year of life) were enrolled on a voluntary basis, AEFIs diaries were used, and their parents were interviewed 25 days after the immunization. There were 2540 children enrolled; 2149/2540 (84.6%) completed the post-vaccination follow-up. Of these, 992 AEFIs were registered with a reporting rate of 46.2 × 100 doses: 883/992 (89.0%) AEFIs were not serious, while 109/992 (11.0%) were serious. For serious AEFIs, the evaluation of causality assessment was performed using the algorithm proposed by the World Health Organisation (WHO): 82/109 consistent causal associations to MMRV immunization were detected (reporting rate of consistent AEFIs: 3.8 × 100 follow-up). All serious AEFIs consistently associated with immunization resulted completely resolved at the follow-up. The reporting rate of seizure consistently associated with immunization was 0.05 × 100, lower than data previous published in the literature that did not report the causality assessment. Because no emerging signals were detected, our data from the active surveillance program confirmed the safety profile of the MMRV vaccine.

Immunogenicity and safety of intramuscular versus subcutaneous administration of a combined measles, mumps, rubella, and varicella vaccine to children 12 to 18 months of age

This randomized trial conducted in France compared intramuscular (IM) and subcutaneous (SC) administration of two doses of a measles, mumps, rubella, and varicella (MMRV) combination vaccine (ProQuad®) administered one month apart to 405 children 12–18 months of age (NCT00402831). The 2-dose regimen of MMRV administered IM was shown to be as immunogenic as the 2-dose regimen administered SC for all antigens 6 weeks post-vaccination for the subjects who were initially seronegative for measles, mumps, rubella, or varicella (lower bounds of the two-sided 95% CIs for the difference in response rates for all antigens greater than −10% [range −2.1 for varicella to −3.0 for mumps]). The antibody response rates for all vaccine antigens 6 weeks after the second dose of MMRV were > 99% in both the IM and SC groups. Fewer subjects in the IM group experienced injection-site AEs compared with the SC group (17.8% and 28.6% post-dose 1, and 20.4% and 29.5% post-dose 2, respectively). From Day 0 to Day 4 post-dose 2, fewer subjects reported erythema and swelling in the IM group than in the SC group (15.4% and 27.0%, and 6.0% and 12.5%, respectively). In both groups, most injection-site AEs started during the first four days after vaccination; their intensity was mainly mild or ≤2.5 cm. The rates of fever were comparable between the two groups after each dose of MMRV. In conclusion, two doses of the MMRV vaccine were highly immunogenic and well tolerated when administered either SC or IM.

ClinicalTrials.gov Identifier: NCT00402831

Sepsis, parenteral vaccination and skin disinfection

ASBSTRACT Disinfection should be required for all skin penetrative procedures including parenteral administration of vaccines. This review analyses medically attended infectious events following parenteral vaccination in terms of their microbiological aetiology and pathogenesis. Like 'clean' surgical site infections, the major pathogens responsible for these events were Staphylococcal species, implicating endogenous con-tamination as a significant source of infection. As 70% isopropyl alcohol swabbing has been shown to effectively disinfect the skin, it would be medico-legally difficult to defend a case of sepsis with the omission of skin disinfection unless the very low risk of this event was adequately explained to the patient and documented prior to vaccination. There was a significant cost-benefit for skin disinfection and cellulitis. Skin disinfection in the context of parenteral vaccination represents a new paradigm of medical practice; the use of a low cost intervention to prevent an event of very low prevalence but of significant cost.

Risk of febrile seizure after measles-mumps-rubella-varicella vaccine: A systematic review and meta-analysis

BACKGROUND

Considering the febrile seizure rate, there is no longer a clear preference for use of measles-mumps-rubella-varicella (MMRV) vaccine over separate measles-mumps-rubella (MMR) and varicella (V) vaccine. This work was undertaken to assess the risk of febrile seizure after MMRV vaccine in children.

METHODS

We searched PubMed, Embase, BIOSIS Previews, Scopus, Web of Science, Cochrane Library and other databases through 12 December 2014. Meta-analysis was conducted using R version 3.1.2 and Stata version 12.0.

RESULTS

A total of thirty-nine studies were included. Thirty-one published or unpublished clinical trials involving about 40,000 subjects did not show significant differences in incidence of febrile seizure or vaccine related febrile seizure between MMRV and MMR with or without varicella vaccine after any doses, in the risk windows of 0-28, 0-42 or 0-56 days and 7-10 days. In addition, these studies showed that the receipt of concomitant use of MMRV and other pediatric vaccines was not a significant predictor of febrile seizure. Eight post-marketing observations involving more than 3,200,000 subjects were included. No evidence suggested elevated risk of febrile seizure associated with MMRV vaccine among children aged 4-6 years old during 7-10 days or 0-42 days after vaccination. However, an approximately 2-fold increase in risk of seizure or febrile seizure during 7-10 days or 5-12 days after MMRV vaccination was found among children aged 10-24 months, although the highest incidence of seizure was still lower than 2.95‰.

CONCLUSIONS

First MMRV vaccine dose in children aged 10-24 months was associated with an elevated risk of seizure or febrile seizure. Further post-marketing restudies based on more rigorous study design are needed to confirm the findings.

Measles-mumps-rubella-varicella combination vaccine (ProQuad): a guide to its use in children in the E.U

In the EU, the live attenuated, tetravalent measles-mumps-rubella-varicella vaccine ProQuad is indicated for simultaneous vaccination against measles, mumps, rubella and varicella in individuals from 12 months of age using a two-dose schedule and may be used in infants from 9 months of age to conform with a national vaccination schedule, outbreak situations or travel to a region with a high prevalence of measles. Clinical data in young children indicates that vaccination with ProQuad is as immunogenic as the component vaccines, provides long-term protection against these potentially serious childhood infections and has an acceptable safety profile. Combining the viral strains of the measles-mumps-rubella vaccine M-M-RVAXPRO and the varicella vaccine Varivax in ProQuad reduces the complexity of vaccination schedules, thereby potentially improving vaccination coverage and the timeliness of vaccination.