Nasal shedding of vaccine viruses after immunization with a Russian-backbone live attenuated influenza vaccine in India

BACKGROUND

We present post-vaccination nasal shedding findings from the phase IV, community-based, triple-blinded RCT conducted to assess efficacy of trivalent LAIV and inactivated influenza vaccines in rural north India.

METHODS

Children aged 2-10 years received LAIV or intranasal placebo across 2015 and 2016, as per initial allocation. On days 2 and 4 post-vaccination, trained study nurses collected nasal swabs from randomly selected subset of trial participants based on operational feasibility, accounting for 10.0% and 11.4% of enrolled participants in 2015 and 2016, respectively. Swabs were collected in viral transport medium and transported under cold chain to laboratory for testing by reverse transcriptase real-time polymerase chain reaction.

RESULTS

In year 1, on day 2 post-vaccination, 71.2% (74/104) of LAIV recipients shed at least one of vaccine virus strains compared to 42.3% (44/104) on day 4. During year 1, on day 2 post-vaccination, LAIV-A(H1N1)pdm09 was detected in nasal swabs of 12% LAIV recipients, LAIV-A(H3N2) in 41%, and LAIV-B in 59%. In year 2, virus shedding was substantially lower; 29.6% (32/108) of LAIV recipients shed one of the vaccine virus strains on day 2 compared to 21.3% on day 4 (23/108).

CONCLUSION

At day 2 post-vaccination in year 1, two-thirds of LAIV recipients were shedding vaccine viruses. Shedding of vaccine viruses varied between strains and was lower in year 2. More research is needed to determine the reason for lower virus shedding and vaccine efficacy for LAIV-A(H1N1)pdm09.

Respiratory syncytial virus infection among adults after hematopoietic stem cell transplantation

Introduction:

Respiratory syncytial virus (RSV) is a common cause of morbidity among hematopoietic stem cell transplant (HSCT) recipients, with RSV-associated lower respiratory tract infection carrying high mortality rates. There have been no large studies till date, describing the incidence, clinical features, and outcomes of RSV infection among adult HSCT recipients in India.

Methods:

A prospective cohort of 100 adults who underwent HSCT was followed up for a maximum period of 18 months starting from the date of transplantation for any episode of respiratory tract infectious disease (RTID). Respiratory samples were collected for laboratory confirmation of the presence and subtyping of RSV by real-time reverse transcriptase-polymerase chain reaction.

Results:

The study population comprised of 66% (66/100) males and 34% (34/100) females. Autologous HSCT recipients constituted 78% (78/100) and allogeneic HSCT recipients constituted 22% (22/100) of the study population. The incidence of RSV-RTID among adults after HSCT was 0.82/100 patient months. Most cases occurred during the winter season and the predominant subtype was RSV-A (9/11, 81.8%). Lower RTID was the most common clinical diagnosis made at presentation (9/11, 81.8%). Female gender was predictive of RSV-RTID (log rank P = 0.002). All the RSV-RTID episodes recovered completely without targeted therapy.

Conclusion:

RSV is a significant cause of morbidity among adult HSCT recipients in India. Prophylaxis and treatment measures need to be instituted after a proper risk-benefit assessment. Longitudinal studies with larger sample sizes are needed to confirm these results.

1767. Incidence of Respiratory Syncytial Virus Infection among Adults Undergoing Hematopoietic Stem Cell Transplantation: A Prospective Study from India

Background

Respiratory Syncytial Virus (RSV) is an important cause of morbidity and mortality in hematopoietic stem cell transplant (HSCT) recipients; progression from Upper Respiratory Tract Infection (URI) to Lower Respiratory Tract Infection (LRTI) may occur in 30%–40% of transplant recipients with associated high fatality. Data on disease burden due to RSV among adult HSCT recipients is limited with no earlier reports from India.

Methods

We prospectively studied 50 HSCT recipients who underwent hematopoietic stem cell transplantation at our institute from January 2017 onwards. Patients were followed up for a period of 18 months post-transplant, initially during stay in transplant unit and subsequently on out-patient basis and telephonically for any episode of acute respiratory tract infection. Information on symptoms and signs at presentation as well as basic hematological and radiological investigations were collected. Nasal and throat swabs from symptomatic patients were taken in viral transport medium and tested for RSV by real-time RT–PCR. As per institute policy patients had received prophylaxis with acyclovir and itraconazole till day +30 post-transplant.

Results

A total of 68 episodes of acute respiratory tract infection were tested for RSV during the follow-up period (mean ± standard deviation = 12 ± 5 months; 11 patients expired during follow-up period). Of these 21 were URI episodes, 46 were acute bronchitis episodes and 1 was a pneumonia episode. Two episodes tested positive for RSV in two autologous HSCT recipients, both belonging to RSV-B subtype, one from a URI episode on day 163 of HSCT and the other from a pneumonia episode on day 8 after HSCT. Both recovered without specific targeted treatment against RSV. The incidence of RSV infection in post-HSCT adult patients calculated from this study is 4% per year.

Conclusion

There is significant incidence of RSV infection among post-HSCT adults in India. Nevertheless, institution of targeted treatment options depends on weighing the cost and risk against benefit of using them. RSV-B subtype as seen in this study also is less virulent and less likely to lead to LRTI compared with RSV-A. Clinical predictors of poor outcomes can also help to decide upon prophylaxis. Larger studies focusing on preventing progression to LRTI need to be done.

Disclosures

All authors: No reported disclosures.

Prevalence and clinical outcome of respiratory viral infections among children with cancer and febrile neutropenia

Background: The role of respiratory viruses (RV) in children with cancer having febrile neutropenic episodes has not been well studied. The objectives of our study were to investigate the prevalence and clinical outcomes of Respiratory viral infection (RVI). Methods: Children with cancer and febrile neutropenia (FN) having acute respiratory infections (ARI) were considered as cases and febrile neutropenic cancer patients without ARI were considered as controls. A throat swab sample was obtained for the detection of 21-respiratory pathogens. Results: A total of 81 episodes of FN in cases and 37 episodes of FN in controls were included. Prevalence of RVI (at least 1 RV) was seen in 76.5% of cases and 48.6% of controls (p = 0.005). The mixed-respiratory viruses (co-infections of ≥2 viruses) were seen only in cases (26%) (p = 0.00). Rhinovirus (36.8%) and respiratory syncytial virus (13.6%) were the most frequently detected viruses. Median duration of fever before presentation was more in cases with RVI compared to without RVI [2 (1-5) days vs 1 (1-5) day (p = 0.012)]. The median total duration of febrile period was 4 (IQR, 3-6) days in cases with RVI and 3 (IQR, 1-4) days in cases without RVI (p = 0.005). The median duration of antibiotic days were longer in cases with RVI as compared to patients without RVI [9 (IQR, 7-17) days vs 7 (IQR, 6-10) days (p = 0.046)] respectively. Conclusion: There was high prevalence of RVI in children with cancer and FN; more in association with ARI. The RVI were associated with prolonged febrile period and days of antibiotics therapy.

Changes in astigmatism in children with congenital nystagmus

BACKGROUND

Astigmatism is commonly reported in children with and without nystagmus. In children less than 4 years of age the astigmatism changes from against the rule (ATR) to with the rule (WTR) astigmatism in children without nystagmus. However, little is known about children with congenital nystagmus. We compared astigmatism in children with congenital nystagmus below 4 years and above 4 years of age.

MATERIAL AND METHODS

Three hundred and fifty-six eyes in 178 children who satisfied the study criteria were included. The children were divided into those below 4 years of age (n of eyes = 192) and those above (n of eyes = 164). Cycloplegic refraction (with manual retinoscopy) carried out at presentation and at the last follow-up were recorded and compared. Cycloplegia was achieved using cyclopentolate eye drops. Outcome of eyes with no astigmatism at initial presentation was compared with the final refraction in both the age groups. The visual acuity at the first presentation was compared with the visual acuity at the last presentation.

RESULTS

Average follow-up duration was 3.36+/-1.59 years. On presentation, 176 (49.44%) eyes did not have any astigmatism. We found that 26 (25.2%) out of the 103 children below 4 years of age who did not have any astigmatism on presentation developed WTR astigmatism after a mean follow-up of 3.5+/-1.5 years. (p= 0.042). In children >or=4 years of age only 7 (9.6%) children out of 73 developed WTR after a mean follow-up of 3.4+/-1.4 years. The visual acuity change was not found to be significant in the two groups. The majority (90.3%) improved or had same visual acuity in group A and 88.9% improved or had the same visual acuity in group B at the last follow-up (p= 0.77).

DISCUSSION

Our incidence of WTR astigmatism in children with congenital nystagmus is similar to those previously reported series. Our data suggest that there is a significant chance that children under 4 years with congenital nystagmus may develop WTR astigmatism compared with children above 4 years of age.

CONCLUSION

With the rule (WTR) astigmatism is common in children with nystagmus. Children under 4 years of age presenting with no astigmatism may acquire WTR astigmatism as they grow. The amount of astigmatism increases with age in children with nystagmus. Visual acuity, however, remains stable as the age advances.