The Global Interest in Vaccines and Its Prediction and Perspectives in the Era of COVID-19. Real-Time Surveillance Using Google Trends

Background: The COVID-19 pandemic has globally overwhelmed all sectors of life. The fast development of vaccines against COVID-19 has had a significant impact on the course of the pandemic. Methods: Global data from Google Trends was analyzed for vaccines against flu, BCG, HPV, pneumococcal disease, polio, and COVID-19. The time frame includes the last five-year period starting from 17 April 2016. Multiple training of time series models with back testing, including Holt–Winters forecasting, Exponential Smoothing State Space, Linear model with trend and seasonal components (tlsm), and ARIMA was conducted. Forecasting according to the best fitting model was performed. Results: Correlation analysis did not reveal a decrease in interest in vaccines during the analyzed period. The prediction models provided a short-term forecast of the dynamics of interest for flu, HPV, pneumococcal and polio vaccines with 5–10% growth in interest for the first quarter of 2022 when compared to the same quarter of 2021. Conclusions: Despite the huge interest in the COVID-19 vaccine, there has not been a detectable decline in the overall interest in the five analyzed vaccines.

Reintroducing OPV in Israel on the journey to global polio eradication - Estimation at a low rate of contraindicated population

INTRODUCTION

The 2013 reemergence of wild poliovirus in Israel led to the reinstatement of a routine OPV vaccination. Fearing VAPP in immunocompromised, the MOH regulated contraindications for vaccination candidates and household contacts. In this study we estimate the size of the contraindicated population to OPV vaccination.

METHOD

We studied vaccination candidates aged 2-9 and 14-23 months and probable household contacts. Using the rate of contraindications extracted for each study group from a medical records database, a statistical model was built to estimate the probability of contraindications in candidates.

RESULTS

3.9% of the 2-9-month-old study group and 4% of the 14-23-month-old group had contraindications by either self or household contacts.

CONCLUSION

A statistical model can provide an estimation of the contraindicated population and can be used in the future when devising vaccination campaigns. In contrast to concerns raised by the MOH, our findings show a smaller than anticipated contraindicated population.

Impact of maternal antibodies and infant gut microbiota on the immunogenicity of rotavirus vaccines in African, Indian and European infants: protocol for a prospective cohort study

INTRODUCTION

Gastroenteritis is the leading cause of morbidity and mortality among young children living in resource-poor settings, majority of which is attributed to rotavirus. Rotavirus vaccination can therefore have a significant impact on infant mortality. However, rotavirus vaccine efficacy in Sub-Saharan Africa and Southeast Asia is significantly lower than in high-income countries. Maternally derived antibodies, infant gut microbiota and concomitant oral polio vaccination have been proposed as potential reasons for poor vaccine performance in low-income settings. The overall aim of this study is to compare the role of maternally derived antibodies and infant gut microbiota in determining immune response to rotavirus vaccine in high-income and low-income settings, using the same vaccine and a similar study protocol.

METHODS AND ANALYSIS

The study is an observational cohort in three countries-Malawi, India and UK. Mothers will be enrolled in third trimester of pregnancy and followed up, along with infants after delivery, until the infant completes two doses of oral rotavirus vaccine (along with routine immunisation). The levels of prevaccination maternally derived rotavirus-specific antibodies (IgG) will be correlated with infant seroconversion and antibody titres, 4 weeks after the second dose of rotavirus vaccine. Both within-country and between-country comparisons of gut microbiome will be carried out between children who seroconvert and those who do not. The impact of oral polio vaccine coadministration on rotavirus vaccine response will be studied in Indian infants.

ETHICS AND DISSEMINATION

Ethical approvals have been obtained from Integrated Research Application System (IRAS, NHS ethics) in UK, College of Medicine Research and Ethics Committee (COMREC) in Malawi and Institutional Review Board (IRB), Christian Medical College, Vellore in India. Participant recruitment and follow-up is ongoing at all three sites. Analysis of data, followed by publication of the results, is expected in 2018.

Did the call for boycott by the Catholic bishops affect the polio vaccination coverage in Kenya in 2015? A cross-sectional study

INTRODUCTION

Polio eradication is now feasible after removal of Nigeria from the list of endemic countries and global reduction of cases of wild polio virus in 2015 by more than 80%. However, all countries must remain focused to achieve eradication. In August 2015, the Catholic bishops in Kenya called for boycott of a polio vaccination campaign citing safety concerns with the polio vaccine. We conducted a survey to establish if the coverage was affected by the boycott.

METHODS

A cross sectional survey was conducted in all the 32 counties that participated in the campaign. A total of 90,157 children and 37,732 parents/guardians were sampled to determine the vaccination coverage and reasons for missed vaccination.

RESULTS

The national vaccination coverage was 93% compared to 94% in the November 2014 campaign. The proportion of parents/guardians that belonged to Catholic Church was 31% compared to 7% of the children who were missed. Reasons for missed vaccination included house not being visited (44%), children not being at home at time of visit (38%), refusal by parents (12%), children being as leep (1%), and various other reasons (5%). Compared to the November 2014 campaign, the proportion of children who were not vaccinated due to parent's refusal significantly increased from 6% to 12% in August 2015.

CONCLUSION

The call for boycott did not affect the campaign significantly. However, if the call for boycott is repeated in future it could have some significant negative implication to polio eradication. It is therefore important to ensure that any vaccine safety issues are addressed accordingly.

Measuring Poliovirus Antigenicity by Surface Plasmon Resonance. Application for Potency Indicating Assays

The D-antigen ELISA is the commonly accepted test for release of inactivated poliovirus containing vaccines. However, this test has a few drawbacks regarding the many variations in the method to quantify the D-unit. The result may depend on method and reagents used which makes standardization of inactivated polio vaccines, based on D-units, to a real challenge. This chapter describes a surface plasmon resonance based method to quantify D-units. The advantage of the calibrated D-antigen assay is the decrease in test variations because no labels, [no incubation times] and no washing steps are necessary. For standardization of both IPV and Sabin IPV, the calibration free concentration analysis could be an improvement as compared to ELISA or other SPR methods because this method combines quantity (particle concentration) and quality (antigenicity) in one assay.

Mapping of the epitopes of poliovirus type 2 in complex with antibodies

The inactivated polio vaccine (IPV) contains poliovirus (PV) samples that belong to serotypes 1, 2 and 3. All three serotypes contain the D-antigen, which induces protective antibodies. The antigenic structure of PVs consists of at least four different antigenic sites and the D-antigen content represents the combined activity of multiple epitopes (Ferguson et al., 1993; Minor, 1990; Minor et al., 1986). The potency of IPV vaccines is determined by measuring the D-antigen content. Several ELISA methods have been developed using polyclonal or monoclonal antibodies (Mabs) in order to quantify the D-antigen content. Characterization of the epitopes recognized by the different Mabs is crucial to map the entire virus surface and ensure the presence of epitopes able to induce neutralizing antibodies. Using a new approach that we developed to study the interaction between monoclonal antibodies and poliovirus type 2, which combines cryo-electron microscopy, image analysis and X-ray crystallography along with identification of exposed amino acids, we have mapped in 3D the epitope sites recognized by three specific Fabs at the surface of poliovirus type 2 (PV2) and characterized precisely the antigenic sites for these Fabs.

Immunogenicity and persistence from different 3-dose schedules of live and inactivated polio vaccines in Chinese infants

BACKGROUND

OPV is the only poliovirus vaccine used in the China EPI system, although IPV is available in the private market. We compared immunigencity and persistence among different schedules of IPV and OPV.

METHODS

536 Chinese infants were enrolled into 4 groups receiving different schedules administered at 2, 3, and 4 months of age: IPV-OPV-OPV, IPV-IPV-OPV, IPV-IPV-IPV, and OPV-OPV-OPV. The I-I-I group received an 18-month IPV booster dose. Blood samples were collected before the first dose, after the third dose, and at 18 months for all groups, and also after the booster dose for the I-I-I group. Polio neutralizing antibody titers were assessed, and seroprotection rates were calculated after primary immunization and at 18 months of age.

RESULTS

Before the first dose, GMTs of the 4 groups ranged from 2.96 to 6.89, and seroprotection rates ranged from 17.6% to 54.3%. After 3 doses, the GMT of the I-O-O and I-I-O groups ranged from 901.09 to 1,110.12, and the GMT of the I-I-I group range was 212.02 to 537.52, significantly lower than for the 2 sequential schedules (P<0.001). Seroprotection rates were 98.1% to 100%, with no significant differences among groups. At 18 months of age, the GMTs declined to a range of 527.00 to 683.44 in the I-O-O and I-I-O groups, and declined to 150.04 to 239.89 in the I-I-I group, significantly lower than for the other 3 groups (P<0.001).

CONCLUSIONS

The sequential schedules achieved high GMTs and seroprotection. The IPV-only schedule achieved high seroprotection but with lower GMTs. Sequential schedules are suitable for China. With the 2 sequential schedules, GMTs remained high at 18 months of age and were not inferior to the OPV-only schedule. Thus, with a sequential schedule, the booster dose could be given at 4 years of age, the same age as the current OPV booster dose.

Structural studies of virus-antibody immune complexes (poliovirus type I): Characterization of the epitopes in 3D

The inactivated polio vaccine (IPV) contains poliovirus (PVs) samples that belong to serotypes 1, 2 and 3. All three serotypes contain the D-antigen, which induces protective antibodies. The antigenic structure of PVs consists of at least four different antigenic sites and the D-antigen content represents the combined activity of multiple epitopes (Ferguson et al., 1993; Minor, 1990; Minor et al., 1986). The potency of IPV vaccines is determined by measuring the D-antigen content. Several ELISA methods have been developed using polyclonal or monoclonal antibodies (Mabs) in order to quantify the D-antigen content. Characterization of the epitopes recognized by the different Mabs is crucial to map the entire virus surface and ensure the presence of epitopes able to induce neutralizing antibodies. In a new approach, combining cryo-electron microscopy and image analysis with X-ray crystallography data available along with identification of exposed amino acids we have mapped in 3D the epitope sites recognized by five specific Fabs and one Mab and characterized precisely the antigenic sites for these Mabs. We propose this method to be used to map the entire "epitopic" surface of virus.

Effect of multiple, simultaneous vaccines on polio seroresponse and associated health outcomes

BACKGROUND

Administration of multiple simultaneous vaccines to infants, children, and military recruits is not uncommon. However, little research exists to examine associated serological and health effects, especially in adults.

METHOD

We retrospectively examined 416 paired serum specimens from U.S. military subjects who had received the inactivated polio vaccine (IPV) alone or in combination with either 1 other vaccine (<3 group) or 4 other vaccines (>4 group). Each of the 2 groups was subdivided into 2 subgroups in which Tdap was present or absent.

RESULTS

The >4 group was associated with a higher proportion of polio seroconversions than the <3 group (95% vs. 58%, respectively, p<0.01). Analysis of the <3 subgroup that excluded Tdap vs. the >4 subgroup that excluded Tdap showed no difference between them (p>0.1). However, the >4 subgroup that included Tdap had significantly more seroconversions than either the <3 subgroup that excluded Tdap or the >4 subgroup that excluded Tdap (p<0.01). Overall, at least 98% of subjects were at or above the putative level of seroprotection both pre- and post-vaccination, yet at least 81% of subjects seroconverted. In an analysis of 400 of the subjects in which clinic in- and outpatient encounters were counted over the course of 1 year following vaccinations, there was no significant difference between the 2 groups (p>0.1).

CONCLUSION

A combination of >4 vaccines including IPV appeared to have an immunopotentiation effect on polio seroconversion, and Tdap in particular was a strong candidate for an important role. The dose of IPV we studied in our subjects, who already had a high level of seroprotection, acted as a booster. In addition, there appear to be no negative health consequences from receiving few versus more multiple simultaneous vaccinations.