Latest COVID wave: When waning immunity, expired vaccines, new strains mix

MANILA, Philippines, August 14 ------ While Octa Research initially expected a two-month COVID-19 wave, it said that the surge is taking longer than expected.

Dr. Guido David, an Octa Research fellow, said 20 provinces—15 in Luzon and five in the Visayas—registered high positivity rates, which were above 20 percent. He said “very high” positivity rates were logged in Capiz (64), Camarines Sur (48.7), Isabela (47.6), Tarlac (41.9), Aklan (40.1), Nueva Ecija (38.4), Pampanga (35), and Laguna (33.2). Positivity rates in Cagayan (30.5), La Union (29.4), Zambales (28.6), Albay (28.2), Bohol (26.9), Quezon (25.1), Pangasinan (25), Negros Oriental (23.4), Benguet (22), Cavite (21.1), Palawan (20.4), and Rizal (18.8) were also deemed concerning. David said he expected a two-month wave because of the Omicron sub-variants BA.4 and BA.5: “We’ve already had two months (June to August) but we’re not yet at the peak, so it’s taking longer.”

The department’s COVID-19 Tracker showed that new cases raised the country’s total caseload to 3,810,772, with 3,713,242 recoveries and 60,864 deaths. Currently, the average national positivity rate is 18.6 percent, almost two percent higher than the previous week’s 16.7 percent. Presenting OCTA Research’s projections, David said at a public briefing that “right now, it’s looking like it will last up to four or five months, well, into the ‘ber’ (September, October, November, December) months.” Last July 26, the DOH warned that daily cases may reach as high as 19,306 by Aug. 31 if vaccination and booster rates, as well as compliance with minimum health protocols, do not improve.

Based on DOH data, 71,523,190 persons have already received complete COVID-19 vaccine doses, but only 16,587,595 persons have been administered booster shots—54,935,595 persons eligible for booster have not yet received any shot. The department stressed that if vaccination and booster rates, as well as compliance with minimum health protocols improve, daily cases will reach only 6,194 to 8,346 by Aug. 31. The government reiterated the need to continue wearing best-fitting face masks, isolating when sick, doubling-up protection through vaccines, and ensuring good airflow to control the spread of SARS-CoV-2, the virus that causes COVID-19. This, as the DOH told reporters last month that the “wall of immunity against COVID-19 is really going down,” stressing that hospitalizations could possibly rise by August and September. David stressed that one of the reasons for the COVID-19 wave is the waning immunity of people who have been administered with the vaccines and the public’s lack of compliance with minimum health protocols.

Based on a study, which was published in The Lancet, vaccine effectiveness wanes five months after the second dose—Pfizer-BioNTech (82.1 percent); AstraZeneca (75.7 percent); and Moderna (75.7 percent). Entitled “COVID-19 Vaccine Waning and Effectiveness and Side-Effects of Boosters,” the study said vaccine efficacy decreased more in people who are 55 years or older and in people with comorbidity. “After five months, vaccine effectiveness remained high among individuals younger than 55 years. Booster doses restore vaccine effectiveness. Adverse reactions after booster doses were similar to those after the second dose,” it said.

David said OCTA Research is not yet recommending the escalation of COVID-19 Alert Levels because of low hospitalization, stressing that ‘we can endure it (rising cases) for now.’ “This is the reason why the government embarked on a vaccination and booster drive so that our hospital utilization rate will not increase and for our economy and our businesses to remain open,” he said.

As the DOH said that the “wall of immunity is really going down,” it stressed the need for Filipinos to get booster shots, saying that there are a lot of reasons for COVID-19 cases to rise. The problem, however, is that there is a looming wastage of up to P13.5 billion worth of unused and expired COVID vaccines while the number of infections continued to reach record-highs. Last Aug. 3, Sen. Risa Hontiveros filed a resolution seeking to investigate why 4 million to 27 million vaccine doses, worth an average of P500 each, were bound to be thrown away. She acknowledged that vaccine doses would be unusable for various reasons and the figure would be tainted with a margin of error.

“But in this case, should we just say goodbye to billion peso-worth of vaccines? We cannot brag that we have outdone Asyong Aksaya because someone has to answer for all these,” she said. “It is reprehensible that billions of pesos could end up squandered amid the continuing threat of COVID-19 and the need to fund the needs of the other sectors heavily affected by the pandemic,” Senate Resolution No. 92 stated. Hontiveros asked: “Were there shortcomings in the processes, and if so, where did these take place? Was it in the purchase? The rollout? The issuance of guidelines? The bottom line is that money and supplies went to waste regardless of whom these came from.”

For Dr. Tony Leachon, there was a need for a “new plan of action” in responding to COVID-19 and vaccination as a new “more transmissible and evasive” Omicron sub-variant threatened the country. David said he was not ruling out the possibility that the “prolonged” wave is caused by the possible spread of the BA.2.75 sub-variant, which “appears to more easily bypass the defenses built up against SARS-CoV-2 through small, specific changes.”

Last month, the World Health Organization stressed that while it was closely monitoring the new version of Omicron, which has already been detected in over 10 countries, “there are still limited sequences available to analyze.” Octa Research said “it’s possible that our wave is getting prolonged because of, maybe, the effects of BA.2.75 that is causing additional infections—this is just a possibility.” It was on Aug. 2 when the DOH detected the country’s first two cases of the BA.2.75 sub-variant. Both cases were from Western Visayas and were already tagged as recovered. Dr. Cynthia Saloma, executive director of the Philippine Genome Center, said since then, the center has so far not found any BA.2.75 in the random COVID-19 samples it had tested. She then went on to say that the BA.5 sub-variant, which is considered as the most dominant Omicron strain, may be the major reason for the COVID-19 wave that the country is experiencing now. “If you consolidate data from Visayas, Mindanao, and Luzon… If you look at this very closely in the past month, the BA.5 is really the most predominant variant that we are sequencing in the Philippines. It’s above 85 percent of our sequence samples,” she said.

David Montefiori, a professor at Duke University Medical Center’s Human Vaccine Institute, told NBC News that BA.5 is about three times less sensitive to neutralizing antibodies from existing COVID-19 vaccines than Omicron’s original version.

Source: inquirer.net