OFFICIALS involved in Covid-19 response on Wednesday, June 30, 2021, urged local government officials to enforce strict border control measures and adhere to the government’s PDITR strategy to prevent the entry of more variant cases.
Cabinet Secretary Karlo Nograles, co-chairperson of the Inter-Agency Task Force (IATF) for the Management of Emerging Infectious Diseases, said the country’s strict quarantine protocols have prevented local transmission of the Delta variant (B.1.617.2), which has been described by the World Health Organization (WHO) as the most transmissible variant of Sars-CoV-2, the virus that causes coronavirus disease 2019 (Covid-19).
All 17 cases of Delta variant detected in the country as of June 27 involved returning overseas Filipino workers who underwent facility-based quarantine and were isolated. One died, while the rest have recovered and were no longer infectious upon release.
The Delta variant has spread to at least 85 countries while its variant, Delta Plus, has been detected in 11 countries. Studies have shown that the Delta variant evades antibodies and raises the risk of hospitalization and death, especially among unvaccinated people.
During a virtual town hall session Wednesday on quarantine protocols, Nograles briefed the local officials on the latest arrival protocols for international passengers contained in IATF Resolution 123-C which was approved on June 28, 2021.
Effective July 1, 2021, inbound travelers who were fully vaccinated in the Philippines regardless of travel history and those vaccinated in other countries who stayed exclusively in “green” countries will undergo seven days of facility-based quarantine and a reverse transcription polymerase chain reaction (RT-PCR) test on the fifth day.
Even with a negative test result, the traveler must complete seven days in the quarantine facility. The rule on fifth day testing is subject for review after 20 days.
“The test will allow us to detect breakthrough infection in fully vaccinated individuals,” Nograles said.
The DOH has yet to come up with a list of “green” countries, or low-risk countries based on disease incidence.
An individual is considered fully vaccinated at least two weeks after receiving a single-dose vaccine or the second dose of a two-dose vaccine. The vaccine must be covered by an emergency use authorization or compassionate special permit in the Philippines, or by an emergency use listing from the WHO.
Those who have not been fully vaccinated must undergo 10 days of facility-based quarantine with a swab test on the seventh day, and four more days of home quarantine.
Scientific basis
Dr. Anna Ong-Lim, a member of the DOH Technical Advisory Group and head of the Infection and Tropical Disease Division of the UP Philippine General Hospital (UP-PGH), reiterated that variants of Sars-CoV-2 are more transmissible than the original strain detected in Wuhan, China.
Citing Gavi, The Vaccine Alliance data, she said a person infected with the original strain could infect two other people.
The Alpha variant (B.1.1.7), which was first reported in the United Kingdom, could infect four or five other people. Alpha was the first variant of concern (VOC) identified by the WHO because of its high transmissibility.
Other VOCs are the Beta (B.1.351) that was first detected in South Africa, Gamma (P.1 or B.1.1.28) which was first reported in Japan among Brazilian tourists, and Delta, which emerged in India.
Among the VOCs, Ong-Lim said the Delta variant is the most worrisome because it is not only highly transmissible, but is also known to cause severe Covid-19.
The Delta variant could infect up to eight other people. Reports from Australia said a person could get infected following a fleeting exposure of a few seconds to the virus.
Ong-Lim noted that surges in new infections in the country have coincided with the detection of variants.
“We have seen how Alpha and Beta variants contributed to our case spikes. We do not want this to happen again,” she said.
Read: Local Alpha, Beta variant cases detected in regions
The government is implementing a 10 plus 4 quarantine strategy, 10 days of facility-based and four days of home quarantine, for inbound international passengers who are not fully vaccinated against Covid-19.
While in quarantine, an unvaccinated traveler is swabbed on the seventh day while the fully vaccinated traveler is swabbed on the fifth day for the virus.
Ong-Lim explained that the accuracy of a swab test for the virus improves to 33 percent on the fourth day following exposure, 62 percent on the fifth day, and 80 percent on the eighth day, she said.
She reiterated that Covid-19 has an incubation period of up to 14 days. Citing studies, she said a person may test negative if tested on the fifth day following exposure, but may develop symptoms on the 10th day. Two days before the symptoms emerge, the infected individual is already contagious.
“The point is that after exposure, symptoms could develop anytime from Day 0 to Day 14. You become contagious two days before the symptoms manifest so it’s very important to follow the 14-day quarantine,” Ong-Lim said.
She presented data from the US Centers for Disease Control and Prevention which showed that the residual risk of transmission lowers as a traveler spends more days in quarantine.
On Day 1, the risk of transmission exceeds 60 percent. This goes down to about 20 percent on Day 6 and eventually to 0.3 percent to 1.4 percent on Day 10 of quarantine.
“There is still risk of transmission on Day 10, but since it’s very low, we made a compromise to reduce facility-based quarantine to 10 days provided that the traveler undergo four more days of home quarantine or facility-based quarantine in the LGU,” Ong-Lim said.
“I hope I was able to show that our aim is to protect everyone - the traveler who comes home from other countries, his or her family who could get infected if the traveler is unknowingly infected, and the community,” she added.
Ong-Lim stressed that the 10 + 4 quarantine strategy is the best strategy to protect the nation from the entry of additional variant cases. (Marites Villamor-Ilano / SunStar Philippines)