Insights into measles virus: Serological surveillance and molecular characterization

BACKGROUND

Measles has been a significant public health concern in Pakistan, especially in the Khyber Pakhtunkhwa (KPK) province, where sporadic and silent epidemics continue to challenge existing control measures. This study aimed to estimate the prevalence and investigate the molecular epidemiology of the measles virus (MeV) in KPK and explore the vaccination status among the suspected individuals.

METHODS

A cross-sectional study was conducted between February and October 2021. A total of 336 suspected measles cases from the study population were analyzed for IgM antibodies using Enzyme-Linked Immunosorbent Assay (ELISA). Throat swabs were randomly collected from a subset of positive cases for molecular analysis. Phylogenetic analysis of MeV isolates was performed using the neighbor-joining method. The vaccination status of individuals was also recorded.

RESULTS

Among the suspected participants, 61.0% (205/336) were ELISA positive for IgM antibodies, with a higher prevalence in males (64.17%) compared to females (57.04%). The majority of cases (36.0%) were observed in infants and toddlers, consistent with previous reports. The majority of IgM-positive cases (71.7%) had not received any dose of measles vaccine, highlighting gaps in vaccine coverage and the need for improved immunization programs. Genetic analysis revealed that all MeV isolates belonged to the B3 genotype, with minor genetic variations from previously reported variants in the region.

CONCLUSION

This study provides valuable insights into the genetic epidemiology of the MeV in KPK, Pakistan. The high incidence of measles infection among unvaccinated individuals highlights the urgency of raising awareness about vaccine importance and strengthening routine immunization programs.

The Resurgence of Measles Infection and its Associated Complications in Early Childhood at a Tertiary Care Hospital in Peshawar, Pakistan

Measles infection is of substantial interest to immunologists due to its paradoxical interaction with the immune system. After the acquisition of the measles infection, secondary infection plays a pivotal role in measles-related deaths. A cross-sectional study conducted between December 2018 and July 2019 is presented here. A total of one hundred children of both genders presented with measles complications were included following WHO criteria. Measles confirmation was done by quantitative determination of anti-measles antibodies (IgM) in patients’ sera while patient-related demographic data, vaccination status, and other clinical information were obtained on a separate form. The number of female patients (52%) slightly exceeded the number of males (48%). 43% of patients’ parents were illiterate, and half of the patients (50%) were from a poor background. The majority of children (76%) who presented with the complications did not receive a measles vaccine. 56% of children were breastfed while 58% received vitamin A supplements but developed complications. The elevated levels of anti-measles IgM were observed in 77% of cases. In both genders, the major complications were pneumonia, lower respiratory tract infection (LRTI), acute diarrhea, diarrhea and LRTI, pneumonia and diarrhea, otitis media and pneumonia, myocarditis and LRTI, and pneumothorax. The majority of the infected children (n = 48) under 12 months of age had associated complications. It has been observed that the measles virus strikes early age children in the northwestern region of Pakistan, which is an alarming situation and is associated with the aforementioned complications, especially in unvaccinated children. Anti-measles IgM is an important serological parameter for early diagnosis of measles infection.

Case Report: Diagnosis of COVID-19 versus Tropical Diseases in Pakistan

A 25-year-old medical student presented in Multan, Pakistan with a high fever, cough, myalgia, and diarrhea consistent with the typical signs and symptoms of novel coronavirus disease (COVID-19). The patient had traveled to high COVID-19–risk areas within Pakistan and had no significant medical and surgical history. Based on nasopharyngeal and oropharyngeal swab testing, the patient was found to be negative for COVID-19. He subsequently developed a diffuse rash and had serology consistent with dengue and measles. The patient was treated symptomatically, and his condition gradually improved over 7 days. This case highlights the high prevalence of many tropical diseases in low-income countries and the need for clinicians to consider alternate diagnoses in addition to testing for COVID-19 during the pandemic.

Pakistan: country report on children's environmental health

Pakistan is a developing country with an estimated population of 220 million, and among them 34% are children. Due to the lack of a proper health care system, particularly in rural areas, children are prone to many environmental hazards. This paper reports about the different environmental health issues faced by children in Pakistan and was presented at the Regional Meeting on Children's Environmental Health at the Chulabhorn Research Institute, Bangkok, Thailand in May 2019. Pakistan is among those countries where polio is still present due to misconceptions, hard-to-reach areas, war zones, political uncertainty, etc. Extensively drug-resistant typhoid is broadly spreading in Pakistan, and this is a very serious concern over antibiotic failure around the world. Pakistan was long considered a region with a low prevalence of human immunodeficiency virus, but now the disease is spreading at an alarming rate. Globally, Pakistan has the third highest burden of maternal, fetal and child mortality. In the last 10 years or so, around 10,000 cases of dengue have been reported with around 800 deaths, including children. Other issues related to children's environmental health in Pakistan include cholera because of poor sanitation and hygiene, respiratory disease due to pollution, exposure to pesticides, diarrhea, occupational hazards as a result of child labor, etc.

Seroprevalence of Transplacentally acquired Measles antibodies in unvaccinated infants at nine months of age and its relation to the feeding practices

BACKGROUND

In recent years Pakistan has faced frequent measles outbreaks killing hundreds of children despite the availability of vaccine for decades. This study was undertaken to determine the persistence of maternal transferred measles antibody levels in infants before measles vaccination with relation to their feeding practices.

METHODS

A cross sectional study was conducted at district Islamabad over 1 year between 1st October 2013 to 30th Sept. 2016. Any infant less than 9 months of age, not suffering from an acute or debilitating illness and not vaccinated was enrolled in the study. After taking written informed consent from parents / guardians, information was collected on a pretested questionnaire. About 3 cc venous blood was taken to quantify any measles IgG antibodies. Data was analyzed by using Epi Info 7.2 version.

RESULTS

Three hundred eighty-four infants were enrolled and were divided into three age groups, 1-90, 91-180 and 181-270 days age groups. Mean age of infants was 4.4 months ±3.2 SD. Male to female ratio was 1.2:1. A level of maternal measles IgG antibodies ≥12 U/ml was taken as protective. Of total 384 infants, 91(24%) had protective measles antibody titters (> 12 U/ml). and 65 (73%) of them were on breast milk. Highest antibody levels were found in 1-90 days age group. Analysis showed that 181-270 days aged infants had 3.1875 more odds of having unprotected/ low levels of antibodies against measles than children aged less than 180 days. Age group < 180 days found to be statistically significant with protective IgG levels (OR: 3.1875, P value: < 0.000063).

CONCLUSION

Measles protective antibodies were found in infants < 180 days age group. Breast feeding provides early protection against measles. Levels drop down to low levels immediately after birth and then after 06 months. It is, therefore, recommended that measles vaccination should be considered for administration at 6 months or even earlier if measles immunity is desired.

Do grandparents influence parents' decision to vaccinate their children? A systematic review

The global reduction in childhood infectious diseases since the 1960s is primarily due to the success of extensive worldwide immunisation campaigns. However, the universal vaccination coverage program appears to have lost momentum in the wake of negative, unfounded claims about the safety of vaccines. While parents of the 21st century have little first-hand knowledge of devastating childhood diseases, grandparents are more likely to remember family and community members who were afflicted. In the current age of vaccine hesitancy and science scepticism, where research-informed arguments are not always persuasive, grandparents, through their experience of the diseases, may positively influence paediatric vaccine uptake. This paper reviews the literature investigating potential direct or indirect influences of grandparents on parents' decisions to vaccinate their children. A database search using the keywords immunisation, vaccination, children and grandparents resulted in 1988 articles. Titles were screened for relevance and seventy-seven results were retained. After the abstracts were read, only five articles that either explored paediatric vaccines, factors promoting and/or inhibiting paediatric vaccine use and decision-making strategies were reviewed. One paper located through Google Scholar, which failed to show up on database searches, was also retained for a total of six papers. While none of the six papers set out to explore the impact of grandparents on vaccine uptake, they found that grandparents were involved to varying degrees in paediatric vaccine uptake within young families. The research clearly showing that grandparents, and older people more generally, promote vaccination uptake is not currently available. The dearth of literature shows the need for research exploring the perceived and real influences of grandparents on childhood vaccination. This will establish whether grandparents' memory and knowledge of preventable childhood infectious diseases could be harnessed as a public health measure to counteract the current, ill-informed, negative attention on paediatric vaccines.

Epidemiological and molecular investigation of a measles outbreak in Punjab, Pakistan, 2013-2015

Despite the availability of an effective vaccine, the measles virus continues to cause significant morbidity and mortality in children worldwide. Molecular characterization of wild-type measles strains is an invaluable component of epidemiological studies or surveillance systems that provides important information pertinent to outbreak linkages and transmission pathways. Serum samples and throat swabs were collected from suspected measles cases from the Punjab province of Pakistan (2013-2015) and further tested for measles immunoglobulin M (IgM) through enzyme-linked immunosorbent assay and reverse-transcriptase polymerase chain reaction for molecular characterization. Among the total of 5415 blood samples, 59% tested positive for measles IgM. Males had a higher infection rate (55%) than females (45%), and the highest frequency of positive cases (63%) was found in the age group of 0 to 5 years. Partial sequencing of the nucleoprotein gene showed that 27 strains belonged to the B3 genotype, whereas 2 viruses were identified as D4. On phylogenetic analysis, Pakistani B3 strains were found to be closely related to previously reported indigenous strains and those from neighboring countries of Iran and Qatar. This is the first report on the detection of the measles B3 genotype from Punjab, Pakistan. The current study shows a high burden of measles infections in Punjab province owing to poor routine immunization coverage in major cities. It is imperative that national health authorities adopt strategic steps on an urgent basis for improvement of routine immunization coverage. Molecular epidemiology of the measles viruses circulating in different parts of the country can provide useful data to manage future outbreaks.

Sero-epidemiology and Risk Factor Analysis of Measles Among Children in Pakistan

Comparative cross sectional study was conducted on blood samples (n = 231) collected from children of 1 to 10 years of age in Punjab Pakistan through convenient sampling method. Indirect haemagglutination assay (IHA) was standardized and used for serodiagnosis and evaluation of humoral immunity against measles. Associated risk factors including age, gender, locale, and vaccination status were analyzed. Geometric mean titre (GMT) of vaccinated individuals was significantly higher (p < 0.001) than that of non-vaccinated individuals showing that IHA titre of vaccinated individuals was a measure of humoral immune response; whereas, in case of non-vaccinated individuals an indicative of exposure to the measles infection.

Identification of measles virus genotype B3 associated with outbreaks in Islamabad, Pakistan, 2013-2015

BACKGROUND

Measles virus infection remains a significant cause of childhood mortality and morbidity despite continued global efforts and the availability of a safe and effective vaccine. Molecular analysis of indigenous measles viruses could provide critical information on outbreak linkages and transmission pathways that can aid the implementation of appropriate control programs in Pakistan.

METHODS

Blood samples and throat swabs were collected from subjects suspected with measles in Islamabad, Pakistan from 2013 to 2015. Serum samples were tested for the presence of measles immunoglobulin M (IgM) antibodies using enzyme-linked immunosorbent assay (ELISA) while throat swabs were used for the isolation (Vero/SLAM cell line) and subsequent characterization and phylogenetic analysis of measles strains.

RESULTS

Of 373 blood samples, 66% tested positive for measles IgM. Male subjects were more often infected (58%) than female (42%) with the highest frequency of positive cases (63%) in the 0-5-years age group. Among the positive cases, only 13% had received one or two doses of the measles vaccine, while 87% were unvaccinated. Of 80 throat swabs, 29 (36%) showed a measles virus-specific cytopathic effect (CPE) and were characterized as genotype B3 through partial sequencing of the nucleoprotein (N) gene. Phylogenetic analysis revealed the Pakistani B3 strains to be closely related to strains from neighboring countries (Iran and Afghanistan) as well as with B3 viruses from the USA, Germany, and the UK.

CONCLUSIONS

The study results showed that despite the availability of an effective vaccine, the burden of measles infections is very high in Pakistan due to poor routine immunization coverage even in major cities, including the capital city of Islamabad. It is imperative that national health authorities take urgent strategic steps to improve routine immunization and implement adequate molecular identification methods to tackle future measles outbreaks.

Measles in Pakistan: Time to make steps towards eradication

World Health Organization (WHO) measles surveillance data report a reduction in cases of measles globally from 67,524 cases in 2015 to 16,846 in 2016, and a reduction in deaths from 546,800 to 114,900 during period of 2000-14. Pakistan is among the five nations where almost a million children did not receive their first dose of measles vaccination, and outbreaks of the disease resulted in 4386 cases in 2011, 14,687 cases in 2012 with 310 deaths. In 2013, about 25,401 cases of measles were reported and 321 affected children died. The measles vaccination coverage is very low in Pakistan for both 1st dose and booster dose. To prevent outbreaks of measles in Pakistan a national vaccination program should be launched side by side with a polio eradication program in each district and township and a campaign should be launched to educate parents on measles vaccination for childrens to reduce the measles case fatality rate.