Did COVID-19 mitigation measures in the United Kingdom impact the transmission of other infectious diseases?

In a recent study posted to the medRxiv* preprint server, researchers explored the impact of the coronavirus disease 2019 (COVID-19) pandemic-associated non-pharmaceutical prevention measures on the transmission of 22 infectious diseases in England.

Background

The efforts to contain the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the early days of the pandemic before the widespread availability of COVID-19 vaccines consisted of government-initiated lockdowns, mask-wearing, and social distancing measures. Public health communications also strongly encouraged hand-washing.

Studies suggest that apart from limiting the transmission of SARS-CoV-2, these measures could have affected the transmission of other pathogens that are airborne or spread through the fecal-oral route.

About the study

In the present study, the researchers used data from three sources — the United Kingdom (U.K.) Health Security Agency, the Royal College of General Practitioners Research and Surveillance Centre, and the U.K. Office for National Statistics — to analyze the transmission patterns of 22 pathogens in England during the COVID-19 pandemic.

The study investigated the transmission of diseases that spread through aerosolized droplets, direct contact, blood, vectors, and the fecal-oral route. Airborne diseases included chickenpox, measles, mumps, rubella, tuberculosis, influenza, pneumococcal disease, pertussis, strep throat, and scarlet fever.

Herpes simplex virus, methicillin-resistant Staphylococcus aureus (MRSA), urinary tract infections, and skin and subcutaneous tissue infections were the investigated diseases that spread through direct contact. Skin and subcutaneous tissue infections include cellulitis, folliculitis, abscesses, trauma-related infections, and other necrotizing or uncomplicated conditions of the skin and subcutaneous fat that result in erythema, inflammation, and pain.

The diseases transmitted via the fecal-oral route comprised hepatitis E, norovirus, shigellosis, cryptosporidiosis, infectious intestinal diseases, and foodborne diseases. Infectious intestinal diseases typically refer to diseases of the small intestine, stomach, or bowels, such as gastroenteritis, typhoid, and cholera, which cause diarrhea, abdominal pain, and vomiting. The vector-transmitted disease examined in the study was Lyme disease, while the blood-borne disease was hepatitis C.

The transmission patterns of these pathogens were examined in association with COVID-19 preventative measures implemented between March 2020 and February 2022 in the U.K. The major measures include the first and second lockdowns, which began on 23 March and 5 November 2020, respectively. The first vaccination administration and the third lockdown, which occurred on subsequent days (4 and 5 January 2021), were also included in the study.

Results

The results reported a decrease in the cases of all infectious diseases except MRSA, Lyme disease, and hepatitis E after the first lockdown. The authors believe that since MRSA predominantly occurs in hospitals, the surge in MRSA cases during the increased hospitalizations during COVID-19 was logical.

While Lyme disease cases did not show a marked decrease during the first lockdown, the number of cases did decrease during the course of the COVID-19 pandemic. Nine out of 10 airborne diseases and four out of the six diseases transmitted through the fecal-oral route displayed a significant reduction in cases from the time the COVID-19 preventative measures were implemented. Tuberculosis was the exception in airborne diseases, which the authors believe could be explained due to delayed diagnoses during lockdowns, or tuberculosis co-infections with COVID-19.

Despite concerns that interruption of routine vaccinations would cause a resurgence of vaccine-preventable infections, diseases such as mumps, measles, rubella, pneumococcal disease, influenza, and pertussis remained suppressed even after restrictions were lifted. However, non-vaccine preventable diseases such as scarlet fever, strep throat, and chickenpox (vaccination not routinely provided in the U.K.) showed a surge after COVID-19 preventative measures were discontinued.

With decreased human interactions and lockdowns resulting in reduced exposure to the environment and common pathogens, concerns were expressed about increased disease outbreaks due to reduced overall immunity. However, the study reported that only four of the 22 examined diseases displayed an increase in transmission beyond the pre-COVID-19 levels. These were chickenpox, skin and subcutaneous infections, herpes simplex, and infectious intestinal diseases.

Conclusions

Overall, the study indicated that COVID-19 non-pharmaceutical mitigation strategies such as lockdowns, social distancing, and hand-washing significantly reduced the spread of other infectious pathogens, especially those transmitted through aerosolized droplets and the fecal-oral route.

Lack of exposure to common pathogens during lockdowns and other social-distancing measures did not reduce the overall immunity and result in disease outbreaks after these measures were discontinued, except for chickenpox, herpes simplex, and skin and intestinal infections. However, whether the increase in the incidence of these four diseases is connected to COVID-19 measures has not been investigated.

Vaccine-preventable diseases remained suppressed even after COVID-19 restrictions were lifted. Still, diseases such as chickenpox surged, highlighting the need to incorporate chickenpox vaccines into the routine vaccination program in the U.K.

*Important notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Written by

Dr. Chinta Sidharthan

Chinta Sidharthan is a writer based in Bangalore, India. Her academic background is in evolutionary biology and genetics, and she has extensive experience in scientific research, teaching, science writing, and herpetology. Chinta holds a Ph.D. in evolutionary biology from the Indian Institute of Science and is passionate about science education, writing, animals, wildlife, and conservation. For her doctoral research, she explored the origins and diversification of blindsnakes in India, as a part of which she did extensive fieldwork in the jungles of southern India. She has received the Canadian Governor General’s bronze medal and Bangalore University gold medal for academic excellence and published her research in high-impact journals.