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Guam has the highest Covid risk, highest breakthrough infection rate in the US

Updated: Sep 21, 2021

Breakthrough cases make up 31% of more than 1,700 positive results in August

By Mar-Vic Cagurangan

While famed for its successful vaccination rollout, Guam topped the list of U.S. red zones with the highest risk of Covid-19 infections.

Guam also has the highest per capita rate of breakthrough cases— infections among fully vaccinated people— showing a 31 percent share of overall positive cases in the month of August.

According to NPR’s Sept. 15 chart, Guam has 115 coronavirus infections per 100,000 people. Covid tests have yielded an average of 183 cases a day, with a 36 percent increase in two weeks.

Guam leads the pack of Category Red states identified as highest-risk places that include Tennessee (with a population of 6.92 million), West Virginia (1.8 million) Wyoming (590,000) and South Carolina (5.2 million).

Source: NPR

NPR said the risk levels were based on a scale developed by the Harvard Global Health Institute in a collaboration of top scientists at various U.S. institutions.

Guam is among the U.S. jurisdictions with the most successful vaccination campaign, ranking No.6 on the New York Times’ tally.

Based on the New York Times chart, 76.1 percent of Guam’s residents 18 years and older are fully vaccinated, and 86 percent among people the same age bracket are partially vaccinated.

Source: New York Times

But despite the high inoculation rate, test results from August revealed an alarming number of breakthrough cases, showing the highest percentage share of overall cases compared to other states that have reported breakthrough data.

According to the record of test results from the Department of Public Health and Social Services, Guam had 1,765 Covid-positive cases in August. Of this number, 554 (or 31 percent of the total for the month) were identified as breakthrough cases, and 128 were partially vaccinated.

Guam’s rate was the highest compared to those of other states during the same month.

In an Aug. 11 report, the New York Times identified Arkansas as the state with the highest rate of breakthrough cases at 4.7 percent. Alaska and Colorado had 2 percent each. The rest had below 1 percent.

As of Sept. 19, Guam has recorded 13,532 positive cases, with 179 deaths and 2,696 cases in active isolation since the first outbreak in March 2020.

Health authorities attribute the Covid surge to the highly transmissible delta variant.

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Of the 82 Covid-related hospitalizations at Guam Memorial Hospital and Guam Regional Medical City, 45 patients were unvaccinated and 12 had unknown vaccination status, leaving 25 confirmed breakthrough hospitalizations. Guam has reported four breakthrough deaths.

There are currently 14 Covid patients in intensive care units of Guam Memorial Hospital and three on ventilators at both hospitals.

Available data indicated that 31 percent of Guam's hospitalizations are breakthrough cases.

Guam's breakthrough hospitalization rate is significantly higher than those of other category red states.

According to Kaizer Foundation, Tennessee has a hospitalization rate of .04 percent, while its breakthrough hospitalization rate is .01 percent.

South Carolina has .42 percent hospitalization rate with .036 percent breakthrough hospitalizations.

West Virginia has .5 percent breakthrough cases with .019 percent breakthrough hospitalizations.

The spiraling number of breakthrough infections has been causing anxiety among some residents, who raise doubts over the efficacy of the Covid-19 vaccines.

The latest record from DPHSS showed Guam has a total of 116,184 (85.25 percent) eligible population (12 years and older) that is fully vaccinated. This includes 9,655 fully vaccinated residents between the ages of 12 and 17, as well as Guam's fully vaccinated adult population of 106,529.


While acknowledging that vaccines are not 100 percent effective, health authorities maintain that getting jabs gives people protection against the coronavirus.

“Vaccines are good,” said Dr. Hoa Nguyen, the former chair of the governor’s Physicians Advisory Group.

He attributed the breakthrough infection surge to high comorbidities on Guam as well as the island’s “family culture.”

“Gatherings are our problem,” Nguyen said.

Medical authorities said most breakthrough infections usually result in mild symptoms.

At last week’s press conference, Dr. Alexander Wielaard, medical director at GRMC, said breakthrough patients are confined in hospitals for a shorter length of time compared to the unvaccinated.

“Vaccinated patients stay about a week, while the unvaccinated stay for an average of two weeks,” Wielaard said at the press conference.

Explaining the increase in the number of breakthrough hospitalizations, Wielaard said every person who comes to the hospital gets tested for Covid.

“So that means, we will inevitably identify people who are positive and there may have been other reasons for being hospitalized that may be complicating their condition,” Wielaard said. “When you are looking at data, you are seeing an absolute worst-case scenario of vaccination performance because you are testing every single person who ends up in ICU.”


At any rate, Wielaard urged the unvaccinated to roll up their sleeves.

“We know that nothing is 100 percent effective, but the vaccine is still an effective intervention,” he said.

The DPHSS’s Sept.10 situation report showed that Covid transmissions mainly occur within households with 3,153 cases were traced through household contacts, while 1,924 were traced through the workplace; 1,555 through the community; and 95 through health care.

The largest number of infections occurred in the northern part of the island, (6,591), followed by the central region (3,190). Southern villages were reported to have 1,699 cases. Four cases involved homeless people and 219 were nonresidents.

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