A study of adult rubella outbreak and its implications on increasing number of women in uniform

Abstract

Background

Rubella, although a fairly innocuous disease, is a known cause of severe birth defects in newborn. With number of women in uniform on the rise and they being assigned instructional and medical care duties, adult rubella outbreak in a training centre as in this study poses grave threat to them; besides, having disruption potential for their training.

Methods

This study was conducted at an Airmen Training Centre of the Indian Air Force having more than 2500 recruits, in five squadrons. All cases of fever with rash and/or lymphadenopathy were included in the study. The demographic, epidemiological and clinical data of all the cases were analyzed and medical records reviewed.

Results

A total of 31 male recruits reported over 5 days. Among those, 21 cases were from a single squadron to which the index belonged. Twelve women officers were doing instructional duties at the time of outbreak though none became infected. Fever with a rash (90.32%) was the commonest presentation, and lymphadenopathy (64.51%) was the most common sign. Attack rate (AR) with-in the squadron most affected was 4.18%, with an overall AR of 1.23%. The case fatality rate of the disease was nil.

Conclusion

Till the fully immunized cohort of young recruits start getting enrolled, it will be prudent to introduce rubella vaccine to limit the loss of vital training man-hours and prevent the possibility of congenital rubella syndrome in the women instructors and medical caregivers, working in the line of their duty.

Introduction

Fever with rash is a non-specific presentation of a variety of infectious and non-infectious causes. The differential diagnosis of fever with rash in young adults can be quite extensive, ranging from a relatively innocuous viral exanthema to more severe and potentially fatal conditions like meningococcaemia, Rocky Mountain spotted fever, viral haemorrhagic fever and so on.¹ Therefore, timely and accurate diagnosis in such cases can be vital and lifesaving. In an institutional setting with more than 2500 trainees, it becomes even more imperative, because of its public health implications.

Rubella is an acute viral infection characterized by fever, rash and lymphadenopathy. The agent responsible is the RNA virus, Togavirus, the only member of the Rubivirus genus. The incubation period is of average 18 days, with a range of 12–23 days. It is primarily a disease of infants and children.² Outbreaks of rubella have rarely been reported among young adults in India, with only a few documented studies on adult rubella outbreaks from the country.^3,4

Indian women have already broken the glass ceiling by getting enrolled into the armed forces as officers into various arms and services and it is just a matter of time before they start getting recruited at the airmen level.⁵ These young women are in their child-bearing age and do get pregnant in due course of their early career. Most of them are unvaccinated, making them vulnerable to rubella and subsequent threat of congenital rubella syndrome (CRS) among their children.

This study describes an outbreak of fever with a rash, which during the course of investigation and control was diagnosed as rubella, in young males at an Airmen Training Centre of the Indian Air Force. It further discusses the implications of such an outbreak on the increasing number of women in uniform, because of the threat of CRS the disease poses.

Materials and methods

This study is a descriptive observational study, conducted at an Airmen Training Center of the Indian Air Force. Population at risk were 2500 recruits, which were undergoing training at the centre, during the time of this outbreak. In the centre, recruits were divided into five squadrons for the training purposes. Each squadron was a mix of different ethnic and social backgrounds who were clubbed in training activities like physical training, meals and breaks between classes, with daily interaction between the squadrons. The demographic, epidemiological and clinical data of all the positive cases were analyzed and medical records reviewed.

Preventive measures were instituted simultaneously to contain the outbreak. Extensive health education regarding the mode of spread, prevention and clinical presentation of rubella was given to the trainees and instructors. Women officers doing instructor duties were sensitized about the disease and CRS. The recruits from squadron with maximum number of cases were segregated from all others. Institutional ethical clearance was obtained for the study. All patients were included after obtaining consent.

A rapid search for the new cases was carried out. All male instructors were given the responsibility of active surveillance of contacts by looking for cases of fever with rash, swelling near the neck and non-specific symptoms like headache, running nose and cough and bring them to medical attention at the earliest. Also, all cases of fever with a rash and/or lymphadenopathy were admitted, and hence effectively segregated.

Data collection

All cases of fever with a rash and/or lymphadenopathy were included in the study. Patients presenting with fever without a rash or lymphadenopathy were excluded. All cases were male as there were no female recruits at the centre. A special billet was earmarked for isolation of the cases, in view of the limited capacity of isolation at local hospitals and the Station Medicare Center.

Case definition

A case of rubella as per Centers for Disease Control and Prevention, Atlanta (CDC)⁶ is defined as follows:

Suspected

Any acute illness with rash, which is generalized, not meeting the criteria of a probable or confirmed case or any other disease.

Probable

An acute illness with generalized maculopapular rash; and temperature more than 99 °F; and enlarged lymph nodes, joint pain, arthritis or conjunctivitis; and absence of linkage to a case of rubella, which is laboratory confirmed; in the absence of any other more likely diagnosis.

Confirmed

A laboratory-confirmed case by isolation of virus; or detection of virus-specific nucleic acid by Polymerase Chain Reaction (PCR); or a substantial rise of IgG antibodies; or positive IgM antibody serologic test for rubella.

Laboratory investigation

Rubella was diagnosed by the examination of acute-phase sera for rubella IgM antibodies in the sample.⁷

Results

Index case reported with fever, maculopapular rash and lymphadenopathy on 14 February, followed by other under-trainees of the same squadron with similar complaints within a time-span of 1 week. Verification of the diagnosis was carried out serologically, with positive IgM antibodies for rubella in blood samples.⁷ Serological tests were also performed for infectious mononucleosis and measles, the other two differential diagnosis, which turned out to be negative in all the above cases.

The epidemic was confirmed, as no case of rubella was reported at the Centre during the last 3 years. The epidemic curve was prepared and is shown in the Fig. 1. The peak of incidence was reached during the 5th day of outbreak with no subsequent secondary peaks, the outbreak tailed off documenting the last case at the end of the week, on 20 February. A total of 31 cases reported over 7 days.

Fig. 1.

Time distribution of rubella cases.

Twenty-one cases were from a single squadron which had index case and all four occupants of the billet of the index case were affected. The average age of the patients was 18.47 ± 1.37 years. The attack rate (AR) with-in the squadron most affected was 4.18%, with an overall AR of 1.23%. The case fatality rate of the disease was nil. At the time of this outbreak, the training establishment had 12 women officers and all of them were in child-bearing age between 25 and 40 years.

Fever with maculopapular rash was the commonest presentations, and was present in 28 (90.32%) cases. Fever was low grade with maximum temperature recorded being 102.5 °F. Lymphadenopathy was seen in 20 (64.51%) patients; cervical, sub-occipital or post-auricular in various combinations. Headache and coryza were reported by 19 (61.29%) and 13 (41.93%) patients, respectively. Two (6.45%) patients also complained of red eye (Table 1).

Table 1.

Clinical profile of cases.

Sign & symptoms	Number reported (%)
Fever with rash	28 (90.32)
Lymphadenopathy	20 (64.51)
Headache	19 (61.29)
Coryza	13 (41.93)
Red eye	02 (6.45)

Discussion

Rubella virus enters the upper respiratory tract during inspiration and proliferates asymptomatically in the body. It is further transmitted to the bloodstream via local lymph nodes. The virus is highly contagious, with close contacts most vulnerable.^8,9 The outbreak remained limited to the recruits in this study and did not spread to the instructors and staff at the centre or to the civilian population residing in the vicinity of the centre. This seems to confirm the observation that the propagation potential of rubella virus in the tropics is limited compared to temperate countries.¹⁰

Similar outbreaks of rubella among military recruits have been reported in other countries.10, 11, 12 The 1.23 per 100 population AR in this outbreak is significantly lower than the 1972 outbreak among military recruits at the Tennessee Naval Air Station, United States, which was 12.8% (p < 0.01)¹⁰ and during the 1966 Greek Naval Training Center outbreak, which was 4.3% (p < 0.001).¹¹ Despite inter-squadron mingling, clustering was noticed in a particular squadron where trainees spent their entire training period and free time together, establishing prolonged close contact as a major environmental factor responsible for the transmission and outbreak.

It is well documented that rubella has teratogenic potential in the early months of pregnancy. It causes congenital anomalies such as blindness and irreversible hearing loss in about 40,000 Indian children annually.¹³ With the government of the day favourably inclined to give greater access to women in combat roles,¹⁴ impact of such an outbreak in a niche population of women in uniform can be significant and long term. Significant because almost all are vulnerable to the disease and long term implications in the form of CRS in their children. It poses a multi-pronged HR challenge, with dimensions of morale, sheltered appointments to those affected and cost of care of dependents with CRS.

Increase in uptake of women as officers has led them also being entrusted with instructional duties at the training centres. As per existing policy, all female government employees, including serving women officers, are granted maternity leave. However, the large majority of them do not avail it in the first trimester of pregnancy, keeping it as a reserve for later part of gestation. Working in training centres mandate these women instructors to work in close contact with the recruits. This makes pregnant un-immunized women officers at training centres vulnerable to the disease.

Of the 12 women officers at the training centre during the time of this outbreak, eight were education officers who were directly involved in the training of the recruits, interacting with them in classrooms, imparting service-specific training and during outdoor physicals. Besides, women had always been medical care providers in the role of medical officers, nursing officers and support staff at the hospital. This potentially exposes them to rubella virus harboured by the recruits and future possibility of CRS.¹⁵

The rubella vaccine is administered to the United States and Singapore armed forces personnel at enrolment.¹⁶ Schoenbaum et al had concluded that the U.S. immunization program for rubella was cost-effective.¹⁷ With the 2020 target of controlling CRS in India,¹⁸ there is a pressing need to immunize all children aged up to 15 years simultaneously. This can only be achieved if immunization is carried out in a campaign mode aiming all 410 million children in the country. Mission Indradhanush launched by the Government of India on 25 December 2014 is a step in this direction.¹⁹

After the campaign, the Measles and Rubella (MR) vaccine will be made part of the national immunization program. It will be administered in two doses at ages 9–12 and 16–24 months. As the vaccine is only manufactured by one industrial unit, the nationwide campaign is being introduced in four phases. In the first phase, Tamil Nadu, Karnataka, Goa, Puducherry and Lakshadweep have been covered.²⁰ Despite a government-initiated efforts of mass vaccination, the cohort of young recruits who will be fully immunized and protected against rubella are still at least a decade away.

Conclusion

It is recommended that till the fully immunized cohort of young recruits start getting enrolled, it will be prudent to introduce rubella vaccine for recruits to limit the loss of vital training man hours and prevent the possibility of CRS in the women instructors and medical caregivers, working in the line of their duty.

Limitation of the study

The authors would like to admit that there existed no documentary evidence of previous vaccination, and the childhood history of rubella was not elicited because of the poor reliability of such history.

Declaration of competing interest

The authors have none to declare.