《TAIPEI TIMES》 NPIs critical to containing COVID-19 spread: experts
Researcher Jen Hsiao-hsuan explains the effectiveness of various nonpharmaceutical interventions in limiting the spread of COVID-19 during an online broadcast yesterday hosted by National Taiwan University College of Public Health professor Tony Chen. Screen grab by Wu Po-hsuan, Taipei Times
By Lee I-chia / Staff reporter
Aside from boosting the nation’s COVID-19 vaccination coverage, implementation of nonpharmaceutical interventions （NPIs） is key to controlling the COVID-19 pandemic, as the Delta variant of SARS-CoV-2 spreads around the world, infecting even fully vaccinated people, public health experts said yesterday.
In his weekly online broadcast on the latest COVID-19 situation, National Taiwan University College of Public Health professor Tony Chen （陳秀熙） analyzed the correlation between number of cases, mortality rates, level of NPIs, vaccination coverage and the GDP of several countries.
The Delta and Alpha variants of SARS-CoV-2 have been the two main strains since May, but the former is rapidly outpacing the latter to become the dominant strain, causing a surge in cases in many countries and more vaccine breakthrough infections, he said.
Breakthrough cases refer to people testing positive for COVID-19, despite being fully vaccinated for at least 14 days.
A US study last month showed that 346 people, or 74 percent, of the 469 cases of COVID-19 associated with multiple summer events and large public gatherings in a town in Massachusetts were fully vaccinated, and genomic sequencing of specimens from 133 patients identified that 90 percent were infected with the Delta variant, he said.
Another study conducted in Israel when the Alpha variant was dominant showed that 39 vaccine breakthrough infections, or 2.6 percent, were found among 1,497 fully vaccinated healthcare professionals, but most of them were asymptomatic or had mild symptoms, he said.
The data suggest that even in places where the vaccination coverage is relatively high, the Delta variant can still cause a small surge in cases, Chen said.
NPIs, such as wearing a mask and maintaining social distancing, are still important to avoid catching the virus, even for people who have completed the vaccine regimen, he added.
An analysis of NPI measures adopted by other countries shows that the most effective measures to lower the reproduction number of COVID-19 are limiting the number of people in gatherings to fewer than 10 and suspending school, Chen’s research team said.
Taiwan should conduct a rolling review of COVID-19 prevention and response guidelines for high-risk public venues, such as gyms, restaurants and wedding banquets, which have been conditionally reopened, the team said.
In Taiwan, Alpha is still the dominant strain, infection and death numbers are relatively low, the NPI level is relatively high and vaccine coverage is growing, so the risk of a local COVID-19 outbreak is expected to remain low, Chen said.
While Taiwan has lowered the nationwide COVID-19 alert to level 2, it should continue to implement NPIs as a key measure to contain the virus, especially in the face of the Delta variant spreading around the world, he added.