Research that may come to affect contact tracing and infection control measures in future measles outbreaks has now been presented. A study of an outbreak of measles in Gothenburg, Sweden, a year ago, shows large differences in the risk of transmission from one patient to another.
Outbreak of measles in Sweden last year shows large differences in the risk of patient transmission
During the measles outbreak in Gothenburg, Sweden, 2017-18, the majority of cases (16 of 28) had ‘breakthrough infections’: that is, measles in previously immunized individuals, many of them being healthcare workers.
‘Breakthrough measles’ did not cause any onward transmission
The study concerned, published in the journal Eurosurveillance, shows that cases with ‘breakthrough measles’ had lower virus levels (a relatively low ‘viral load’) in the upper respiratory tract, and had less cough, than measles in unvaccinated individuals. Moreover, the former did not cause any onward transmission.
‘Breakthrough infections’
‘Breakthrough infections’ seem to be much less contagious, and we could not identify any onward transmission from individuals with a breakthrough infection,’ states Nicklas Sundell, the first author of the study, a researcher at Sahlgrenska Academy and infectious disease doctor at Sahlgrenska University Hospital (SU).
Study shows it’s feasible to distinguish breakthrough infections from ‘naïve’ infections
A regular clinical investigation yields no reliable answer about the type of measles a person has: the breakthrough type of measles infection or the highly infectious ‘naïve’ (‘first-time’ or primary measles) type. However, the study shows that it is feasible, with routine laboratory methods, to distinguish breakthrough infections from ‘naïve’ infections.
The results
According to the researchers, the results should help to rapidly identify who has which type of measles during an outbreak, thereby facilitating infection control measures by limiting contact tracing around breakthrough infections.
‘To identify breakthrough infections at an early stage, we propose a fast-provisional classification to support decisions on contract-tracing measures during a measles outbreak,’ says Associate Professor Lars-Magnus Andersson, the senior researcher behind the study, and also Senior Consultant and Head of the Department of Infection Prevention and Control at SU.
‘Vaccine infections’ (caused by the vaccine itself) also diagnosed
Of 28 measles cases identified the Gothenburg outbreak, 16 were breakthrough infections and 12 naïve infections. In addition, six ‘vaccine infections’ (caused by the vaccine itself) were also diagnosed. In the study, patient records were reviewed retrospectively and all cases of measles infection were classified as either naïve, breakthrough or vaccine infection.
Comparisons of clinical data and viral load
Comparisons of clinical data and viral load were carried out between naïve and breakthrough infections. The study was performed in collaboration with the Departments of Communicable Disease Control in Region Västra Götaland and the infectious-disease control unit at Sahlgrenska University Hospital.
From the University of Gothenburg
- Sundell, N. et al. (2019) Measles outbreak in Gothenburg urban area, Sweden, 2017 to 2018: low viral load in breakthrough infections. Eurosurveillance. doi.org/10.2807/1560-7917.ES.2019.24.17.1900114.
Razi Berry is the founder and publisher of the journal Naturopathic Doctor News & Review, which has been in print since 2005, and the premier consumer-faced website of naturopathic medicine, NaturalPath. She is the host of The Natural Cancer Prevention Summit and The Heart Revolution-Heal, Empower and Follow Your Heart, and the popular 10 week Sugar Free Summer program. From a near death experience as a young girl that healed her failing heart, to later overcoming infertility and Chronic Fatigue Syndrome and Fibromyalgia through naturopathic medicine, Razi has lived the mind/body healing paradigm. Her projects uniquely capture the tradition and philosophy of naturopathy: The healing power of nature, the vital life force in every living thing and the undeniable role that science and mind/body medicine have in creating health and overcoming dis-ease. Follow Razi on Facebook at Razi Berry and join us at Love is Medicine to explore the convergence of love and health.
