Monthly Review: COVID-19 Data and Surveillance – November 22, 2021

Monthly Review: COVID-19 Data and Surveillance – November 22, 2021

Negative Test and Airline Travel

This article analyzes results of a routine SARC-CoV-2 testing strategy for international flights during the time period of December 19, 2020 – May 19, 2021.  The collaborative effort between Delta Air Lines, Mayo Clinic, and the Georgia Department of Health sought to review and model testing strategies for case-detection, feasibility, and false-positives.  They implemented a testing protocol to determine if testing within 72 hours of departure could aid in identifying risk of transmission during air travel.  Flights departing U.S. and arriving in Italy were included in the analysis; the infection prevalence at the time was 1.1%.  Passengers were required to submit a negative PCR test within 72 hours of departure and they also had a rapid antigen and molecular test prior to boarding.  If either were positive, then they were not allowed to board.  There were 9,853 passengers who submitted a negative PCR test within 72 hours of departure of which four tested positive with rapid testing prior to boarding.  Given waning immunity and breakthrough infections, evidence of a negative test within 72 hours of air travel seems to be an effective strategy to minimize infection transmission during air travel and has two very important applications: 1) reduce individual risk by detecting infected passengers and preventing their travel; and 2) reduce the number of infections to a new city which reduces the impact of travel on population-level transmission risk.

Routine Childhood Vaccinations

The pandemic has led to a number of adverse outcomes and one worth noting is the major decrease in routine childhood vaccinations that has left millions of children worldwide at risk from preventable diseases like measles, meningitis, or polio.  This article addresses this very issue by comparing trends in childhood vaccination rates before the onset of the pandemic and during using a pre-post control design.  The authors also evaluate children that are up-to-date with vaccinations by demographic factors such as age, race, and ethnicity.  Data were from eight health systems and were obtained from the Vaccine Safety Datalink and age groups for analysis included those <24 months, 4-6 years, 11-13 years, and 16-18 years.  The time period included in the analysis ranged from January 6, 2019 – October 5 2019 (pre-) and January 5, 2020 – October 3, 2020 (post-).  There were approximately 1.4 million children in each time period; the researchers identified substantially lower rates of weekly routine vaccine administration across the aforementioned age groups during first few months of the pandemic.  Specifically,  mean weekly vaccination rates per 1000 population in 2020 for all age groups were lower than 2019 rates and this was most seen in the youngest age group (<24 months: 194.6 [95% CI, 191.3-197.9] per 1000 in 2019 vs 160.1 [95% CI, 157.1-163.0] per 1000 in 2020).   Decreases in the proportions of up to date vaccinations were noted for infants reaching 7 and 18 months of age in May 2020 and September 2020 (infants reaching 7 months: May 2020, 72% [95% CI, 71%-73%]; September 2020, 74% [95% CI, 73%-76%]; 18 months: May 2020, 56% [95% CI, 55%-57%]; September 2020, 57% [95% CI, 56%-58%].  Another decrease was seen for children turning 13 years ( 56% [95% CI, 55%-57%]). Racial differences in vaccine administration were also observed.  For example, the proportion of those with up to date vaccinations at 7 months was highest in Asian children at 88% [95% CI, 86%-90%] and lowest in Black children at 61% [95% CI, 55%-67%]. It is important to note, however, that these differences were similar to those present pre-pandemic.  When observing children at 18 months, rates of those with up-to-date vaccinations were highest in Asian children at 76% [95% CI, 74%-78%] and lowest in Black children at 41% [95% CI, 37%-45%].  These differences and low rates of routine vaccinations indicate the need to improve health care system and community level interventions to protect children from vaccine preventable diseases.

The findings above illustrate vaccination rates in the U.S. but when observing trends worldwide, approximately 23 million children have not received basic routine vaccinations.  In 2019, that number was around 19 million.  According to the WHO and UNICEF,  majority of countries in 2020 experienced decreases in childhood routine vaccination rates.  Furthermore, up to 17 million children most likely did not receive even one routine vaccination during 2020 which is alarming.  The table below displays countries with the greatest increase in children who did not receive the first dose of the DPT-1 vaccine.

2019 2020
India 1,403,000 3,038,000
Pakistan 567,000 968,000
Indonesia 472,000 797,000
Philippines 450,000 557,000
Mexico 348,000 454,000
Mozambique 97,000 186,000
Angola 399,000 482,000
United Republic of Tanzania 183,000 249,000
Argentina 97,000 156,000
Venezuela 75,000 134,000
Mali 136,000 193,000


Significant effort has been made for decades to reduce the risk of vaccine-preventable diseases such as measles, diphtheria, tetanus, pertussis, and polio.  If these efforts are reversed or even negatively impacted, then millions of children worldwide will be at risk of fatal, vaccine-preventable diseases.  The article lists strategies that can be used to increase routine childhood vaccinations:

  • Restoring services and vaccination campaigns so countries can safely deliver routine immunization programs during the COVID-19 pandemic;
  • Helping health workers and community leaders communicate actively with caregivers to explain the importance of vaccinations;
  • Rectifying gaps in immunization coverage, including identifying communities and people who have been missed during the pandemic.
  • Ensuring that COVID-19 vaccine delivery is independently planned for and financed and that it occurs alongside, and not at the cost of childhood vaccination services.
  • Implementing country plans to prevent and respond to outbreaks of vaccine-preventable diseases, and strengthen immunization systems as part of COVID-19 recovery efforts
|2021-11-22T10:48:13-05:00November 22nd, 2021|COVID-19 Literature|Comments Off on Monthly Review: COVID-19 Data and Surveillance – November 22, 2021

About the Author: James Dudley

James Dudley

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